diff --git a/.gitignore b/.gitignore
index 95ca89299..452f2cd84 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,4 +16,6 @@ activity_browser/ABSettings.json
 *.bak
 /.idea
 /.vscode
-.coverage
\ No newline at end of file
+.coverage
+.logs
+test/.logs
diff --git a/activity_browser/__init__.py b/activity_browser/__init__.py
index 643ce3879..5641d521b 100644
--- a/activity_browser/__init__.py
+++ b/activity_browser/__init__.py
@@ -9,7 +9,11 @@
 from .application import Application
 from .info import __version__
 from .plugin import Plugin
+import logging
+from .logger import ABHandler
 
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
 
 # https://bugreports.qt.io/browse/QTBUG-87014
 # https://bugreports.qt.io/browse/QTBUG-85546
@@ -20,11 +24,11 @@
     if QSysInfo.productVersion() not in supported:
         os.environ["QT_MAC_WANTS_LAYER"] = "1"
         os.environ["QTWEBENGINE_CHROMIUM_FLAGS"] = "--disable-gpu"
-        print("Info: GPU hardware acceleration disabled")
+        log.info("Info: GPU hardware acceleration disabled")
 
 if QSysInfo.productType() in ["arch","nixos"]:
     os.environ["QTWEBENGINE_CHROMIUM_FLAGS"] = "--no-sandbox"
-    print("Info: QtWebEngine sandbox disabled")
+    log.info("Info: QtWebEngine sandbox disabled")
 
 def run_activity_browser():
     qapp = QApplication(sys.argv)
@@ -39,10 +43,10 @@ def run_activity_browser():
 #    )
     application = Application()
     application.show()
-    print("Qt Version:", qt_version)
+    log.info("Qt Version:", qt_version)
 
     def exception_hook(*args):
-        print(''.join(traceback.format_exception(*args)))
+        log.warning(''.join(traceback.format_exception(*args)))
 
     sys.excepthook = exception_hook
 
diff --git a/activity_browser/bwutils/calculations.py b/activity_browser/bwutils/calculations.py
index fd3b3b0f3..8557815c3 100644
--- a/activity_browser/bwutils/calculations.py
+++ b/activity_browser/bwutils/calculations.py
@@ -6,9 +6,13 @@
     SuperstructureContributions, SuperstructureMLCA,
 )
 from bw2calc.errors import BW2CalcError
-import brightway2 as bw
 
-from .errors import ReferenceFlowValueError
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 def do_LCA_calculations(data: dict):
     """Perform the MLCA calculation."""
@@ -39,7 +43,7 @@ def do_LCA_calculations(data: dict):
         except KeyError as e:
             raise BW2CalcError("LCA Failed", str(e)).with_traceback(e.__traceback__)
     else:
-        print('Calculation type must be: simple or scenario. Given:', cs_name)
+        log.error('Calculation type must be: simple or scenario. Given:', cs_name)
         raise ValueError
 
     mlca.calculate()
diff --git a/activity_browser/bwutils/commontasks.py b/activity_browser/bwutils/commontasks.py
index 28360de93..4c4b395fb 100644
--- a/activity_browser/bwutils/commontasks.py
+++ b/activity_browser/bwutils/commontasks.py
@@ -9,6 +9,12 @@
 from bw2data.proxies import ActivityProxyBase
 from bw2data.project import ProjectDataset, SubstitutableDatabase
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 """
 bwutils is a collection of methods that build upon brightway2 and are generic enough to provide here so that we avoid 
 re-typing the same code in different parts of the Activity Browser.
@@ -65,7 +71,7 @@ def format_activity_label(key, style='pnl', max_length=40):
 def switch_brightway2_dir(dirpath):
     bw_base = bw.projects._base_data_dir
     if dirpath == bw_base:
-        print('dirpath already loaded')
+        log.info('dirpath already loaded')
         return False
     try:
         assert os.path.isdir(dirpath)
@@ -79,10 +85,10 @@ def switch_brightway2_dir(dirpath):
             os.path.join(bw.projects._base_data_dir, "projects.db"),
             [ProjectDataset]
         )
-        print('Loaded brightway2 data directory: {}'.format(bw.projects._base_data_dir))
+        log.info('Loaded brightway2 data directory: {}'.format(bw.projects._base_data_dir))
         return True
     except AssertionError:
-        print('Could not access BW_DIR as specified in settings.py')
+        log.error('Could not access BW_DIR as specified in settings.py')
         return False
 
 
@@ -92,7 +98,7 @@ def cleanup_deleted_bw_projects() -> None:
     NOTE: This cannot be done from within the AB.
     """
     n_dir = bw.projects.purge_deleted_directories()
-    print('Deleted {} unused project directories!'.format(n_dir))
+    log.info('Deleted {} unused project directories!'.format(n_dir))
 
 
 # Database
@@ -136,7 +142,7 @@ def count_database_records(name: str) -> int:
     try:
         return len(db)
     except TypeError as e:
-        print("{}. Counting manually".format(e))
+        log.error("{}. Counting manually".format(e))
         return sum(1 for _ in db)
 
 
@@ -250,7 +256,7 @@ def get_exchanges_in_scenario_difference_file_notation(exchanges):
 
         except:
             # The input activity does not exist. remove the exchange.
-            print("Something did not work with the following exchange: {}. It was removed from the list.".format(exc))
+            log.error("Something did not work with the following exchange: {}. It was removed from the list.".format(exc))
     return data
 
 
diff --git a/activity_browser/bwutils/metadata.py b/activity_browser/bwutils/metadata.py
index 389cd39c0..f909d53d9 100644
--- a/activity_browser/bwutils/metadata.py
+++ b/activity_browser/bwutils/metadata.py
@@ -7,6 +7,11 @@
 
 from .commontasks import count_database_records
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
 
 # todo: extend store over several projects
 
@@ -61,12 +66,12 @@ def add_metadata(self, db_names_list: list) -> None:
 
         dfs = list()
         dfs.append(self.dataframe)
-        print('Current shape and databases in the MetaDataStore:', self.dataframe.shape, self.databases)
+        log.info('Current shape and databases in the MetaDataStore:', self.dataframe.shape, self.databases)
         for db_name in new:
             if db_name not in bw.databases:
                 raise ValueError('This database does not exist:', db_name)
 
-            print('Adding:', db_name)
+            log.info('Adding:', db_name)
             self.databases.add(db_name)
 
             # make a temporary DataFrame and index it by ('database', 'code') (like all brightway activities)
@@ -113,7 +118,7 @@ def update_metadata(self, key: tuple) -> None:
             act = bw.get_activity(key)  # if this does not work, it has been deleted (see except:).
         except (UnknownObject, ActivityDataset.DoesNotExist):
             # Situation 1: activity has been deleted (metadata needs to be deleted)
-            print('Deleting activity from metadata:', key)
+            log.warning('Deleting activity from metadata:', key)
             self.dataframe.drop(key, inplace=True)
             # print('Dimensions of the Metadata:', self.dataframe.shape)
             return
@@ -124,13 +129,13 @@ def update_metadata(self, key: tuple) -> None:
             self.add_metadata([db])
         else:
             if key in self.dataframe.index:  # Situation 2: activity has been modified (metadata needs to be updated)
-                print('Updating activity in metadata: ', act, key)
+                log.info('Updating activity in metadata: ', act, key)
                 for col in self.dataframe.columns:
                     self.dataframe.at[key, col] = act.get(col, '')
                 self.dataframe.at[key, 'key'] = act.key
 
             else:  # Situation 3: Activity has been added to database (metadata needs to be generated)
-                print('Adding activity to metadata:', act, key)
+                log.info('Adding activity to metadata:', act, key)
                 df_new = pd.DataFrame([act.as_dict()], index=pd.MultiIndex.from_tuples([act.key]))
                 df_new['key'] = [act.key]
                 self.dataframe = pd.concat([self.dataframe, df_new], sort=False)
@@ -140,7 +145,7 @@ def update_metadata(self, key: tuple) -> None:
     def reset_metadata(self) -> None:
         """Deletes metadata when the project is changed."""
         # todo: metadata could be collected across projects...
-        print('Reset metadata.')
+        log.info('Reset metadata.')
         self.dataframe = pd.DataFrame()
         self.databases = set()
 
@@ -210,7 +215,7 @@ def get_units(self, db_name: str) -> set:
     def print_convenience_information(self, db_name: str) -> None:
         """ Reports how many unique locations and units the database has.
         """
-        print("{} unique locations and {} unique units in {}".format(
+        log.info("{} unique locations and {} unique units in {}".format(
             len(self.get_locations(db_name)), len(self.get_units(db_name)),
             db_name
         ))
diff --git a/activity_browser/bwutils/montecarlo.py b/activity_browser/bwutils/montecarlo.py
index a741f0c00..67314eeda 100644
--- a/activity_browser/bwutils/montecarlo.py
+++ b/activity_browser/bwutils/montecarlo.py
@@ -11,6 +11,12 @@
 
 from .manager import MonteCarloParameterManager
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class MonteCarloLCA(object):
     """A Monte Carlo LCA for multiple reference flows and methods loaded from a calculation setup."""
@@ -228,7 +234,7 @@ def calculate(self, iterations=10, seed: int = None, **kwargs):
                     self.lca.lcia_calculation()
                     self.results[iteration, row, col] = self.lca.score
 
-        print('Monte Carlo LCA: finished {} iterations for {} reference flows and {} methods in {} seconds.'.format(
+        log.info('Monte Carlo LCA: finished {} iterations for {} reference flows and {} methods in {} seconds.'.format(
             iterations,
             len(self.func_units),
             len(self.methods),
@@ -254,10 +260,10 @@ def get_results_by(self, act_key=None, method=None):
 
         if act_key:
             act_index = self.activity_index.get(act_key)
-            print('Activity key provided:', act_key, act_index)
+            log.info('Activity key provided:', act_key, act_index)
         if method:
             method_index = self.method_index.get(method)
-            print('Method provided', method, method_index)
+            log.info('Method provided', method, method_index)
 
         if not act_key and not method:
             return self.results
@@ -266,7 +272,7 @@ def get_results_by(self, act_key=None, method=None):
         elif method and not act_key:
             return np.squeeze(self.results[:, :, method_index])
         elif method and act_key:
-            print(act_index, method_index)
+            log.info(act_index, method_index)
             return np.squeeze(self.results[:, act_index, method_index])
 
     def get_results_dataframe(self, act_key=None, method=None, labelled=True):
@@ -317,7 +323,7 @@ def get_labels(key_list, fields: list = None, separator=' | ',
 def perform_MonteCarlo_LCA(project='default', cs_name=None, iterations=10):
     """Performs Monte Carlo LCA based on a calculation setup and returns the
     Monte Carlo LCA object."""
-    print('-- Monte Carlo LCA --\n Project:', project, 'CS:', cs_name)
+    log.info('-- Monte Carlo LCA --\n Project:', project, 'CS:', cs_name)
     bw.projects.set_current(project)
 
     # perform Monte Carlo simulation
@@ -330,14 +336,14 @@ def perform_MonteCarlo_LCA(project='default', cs_name=None, iterations=10):
     mc = perform_MonteCarlo_LCA(project='ei34', cs_name='kraft paper', iterations=15)
 
     # test the get_results_by() method
-    print('\nTesting the get_results_by() method')
+#    print('\nTesting the get_results_by() method')
     act_key = mc.activity_keys[0]
     method = mc.methods[0]
-    print(mc.get_results_by(act_key=act_key, method=method))
+#    print(mc.get_results_by(act_key=act_key, method=method))
     #    print(mc.get_results_by(act_key=act_key, method=None))
     #    print(mc.get_results_by(act_key=None, method=method))
     #    print(mc.get_results_by(act_key=None, method=None))
 
     # testing the dataframe output
-    print(mc.get_results_dataframe(method=mc.methods[0]))
-    print(mc.get_results_dataframe(act_key=mc.activity_keys[0]))
\ No newline at end of file
+#    print(mc.get_results_dataframe(method=mc.methods[0]))
+#    print(mc.get_results_dataframe(act_key=mc.activity_keys[0]))
\ No newline at end of file
diff --git a/activity_browser/bwutils/multilca.py b/activity_browser/bwutils/multilca.py
index 6db306332..c57e45f58 100644
--- a/activity_browser/bwutils/multilca.py
+++ b/activity_browser/bwutils/multilca.py
@@ -12,6 +12,12 @@
 from .metadata import AB_metadata
 from .errors import ReferenceFlowValueError
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class MLCA(object):
     """Wrapper class for performing LCA calculations with many reference flows and impact categories.
@@ -487,7 +493,7 @@ def join_df_with_metadata(cls, df, x_fields=None, y_fields=None,
                 complete_index = special_keys + keys
                 joined = joined.reindex(complete_index, axis="index", fill_value=0.)
             except:
-                print('Could not put Total and Rest on positions 0 and 1 in the dataframe.')
+                log.error('Could not put Total and Rest on positions 0 and 1 in the dataframe.')
         joined.index = cls.get_labels(joined.index, fields=x_fields)
         return joined
 
diff --git a/activity_browser/bwutils/pedigree.py b/activity_browser/bwutils/pedigree.py
index 2d5146a60..1a1e7b863 100644
--- a/activity_browser/bwutils/pedigree.py
+++ b/activity_browser/bwutils/pedigree.py
@@ -13,7 +13,6 @@
 smoothly into the related uncertainty distributions.
 """
 import math
-from pprint import pformat
 
 from bw2data.parameters import ParameterBase
 from bw2data.proxies import ExchangeProxyBase
diff --git a/activity_browser/bwutils/sensitivity_analysis.py b/activity_browser/bwutils/sensitivity_analysis.py
index 50de03f19..ac70e5d23 100644
--- a/activity_browser/bwutils/sensitivity_analysis.py
+++ b/activity_browser/bwutils/sensitivity_analysis.py
@@ -17,13 +17,19 @@
 from .montecarlo import MonteCarloLCA, perform_MonteCarlo_LCA
 from ..settings import ab_settings
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 def get_lca(fu, method):
     """Calculates a non-stochastic LCA and returns a the LCA object."""
     lca = bw.LCA(fu, method=method)
     lca.lci()
     lca.lcia()
-    print('Non-stochastic LCA score:', lca.score)
+    log.info('Non-stochastic LCA score:', lca.score)
 
     # add reverse dictionaries
     lca.activity_dict_rev, lca.product_dict_rev, lca.biosphere_dict_rev = lca.reverse_dict()
@@ -42,7 +48,7 @@ def filter_technosphere_exchanges(fu, method, cutoff=0.05, max_calc=1e4):
     for e in res['edges']:
         if e['to'] != -1:  # filter out head introduced in graph traversal
             technosphere_exchange_indices.append((e['from'], e['to']))
-    print('TECHNOSPHERE {} filtering resulted in {} of {} exchanges and took {} iterations in {} seconds.'.format(
+    log.info('TECHNOSPHERE {} filtering resulted in {} of {} exchanges and took {} iterations in {} seconds.'.format(
         res['lca'].technosphere_matrix.shape,
         len(technosphere_exchange_indices),
         res['lca'].technosphere_matrix.getnnz(),
@@ -57,16 +63,11 @@ def filter_biosphere_exchanges(lca, cutoff=0.005):
     category in a non-stochastic LCA."""
     start = time()
 
-    # print('LCA score:', lca.score)
     inv = lca.characterized_inventory
-    # print('Characterized inventory:', inv.shape, inv.nnz)
     finv = inv.multiply(abs(inv) > abs(lca.score/(1/cutoff)))
-    # print('Filtered characterized inventory:', finv.shape, finv.nnz)
     biosphere_exchange_indices = list(zip(*finv.nonzero()))
-    # print(biosphere_indices[:2])
     explained_fraction = finv.sum() / lca.score
-    # print('Explained fraction of LCA score:', explained_fraction)
-    print('BIOSPHERE {} filtering resulted in {} of {} exchanges ({}% of total impact) and took {} seconds.'.format(
+    log.info('BIOSPHERE {} filtering resulted in {} of {} exchanges ({}% of total impact) and took {} seconds.'.format(
         inv.shape,
         finv.nnz,
         inv.nnz,
@@ -122,7 +123,7 @@ def drop_no_uncertainty_exchanges(excs, indices):
         if exc.get('uncertainty type') and exc.get('uncertainty type') >= 1:
             excs_no.append(exc)
             indices_no.append(ind)
-    print('Dropping {} exchanges of {} with no uncertainty. {} remaining.'.format(
+    log.info('Dropping {} exchanges of {} with no uncertainty. {} remaining.'.format(
         len(excs) - len(excs_no), len(excs), len(excs_no)
     ))
     return excs_no, indices_no
@@ -192,7 +193,7 @@ def get_CF_dataframe(lca, only_uncertain_CFs=True):
         data[params_index]['index'] = cf_index
         data[params_index]['GSA name'] = "CF: " + bio_act['name'] + str(bio_act['categories'])
 
-    print('CHARACTERIZATION FACTORS filtering resulted in including {} of {} characteriation factors.'.format(
+    log.info('CHARACTERIZATION FACTORS filtering resulted in including {} of {} characteriation factors.'.format(
         len(data),
         len(lca.cf_params),
     ))
@@ -206,10 +207,10 @@ def get_parameters_DF(mc):
     if bool(mc.parameter_data):  # returns False if dict is empty
         dfp = pd.DataFrame(mc.parameter_data).T
         dfp['GSA name'] = "P: " + dfp['name']
-        print('PARAMETERS:', len(dfp))
+        log.info('PARAMETERS:', len(dfp))
         return dfp
     else:
-        print('PARAMETERS: None included.')
+        log.info('PARAMETERS: None included.')
         return pd.DataFrame()  # return emtpy df
 
 
@@ -299,10 +300,10 @@ def perform_GSA(self, act_number=0, method_number=0,
         except Exception as e:
             traceback.print_exc()
             # todo: QMessageBox.warning(self, 'Could not perform Delta analysis', str(e))
-            print('Initializing the GSA failed.')
+            log.error('Initializing the GSA failed.')
             return None
 
-        print('-- GSA --\n Project:', bw.projects.current, 'CS:', self.mc.cs_name,
+        log.info('-- GSA --\n Project:', bw.projects.current, 'CS:', self.mc.cs_name,
               'Activity:', self.activity, 'Method:', self.method)
 
         # get non-stochastic LCA object with reverse dictionaries
@@ -378,12 +379,12 @@ def perform_GSA(self, act_number=0, method_number=0,
         #     self.Y = np.log(np.abs(self.Y))  # this makes it more robust for very uneven distributions of LCA results
         if np.all(self.Y > 0):  # all positive numbers
             self.Y = np.log(np.abs(self.Y))
-            print('All positive LCA scores. Log-transformation performed.')
+            log.info('All positive LCA scores. Log-transformation performed.')
         elif np.all(self.Y < 0):  # all negative numbers
             self.Y = -np.log(np.abs(self.Y))
-            print('All negative LCA scores. Log-transformation performed.')
+            log.info('All negative LCA scores. Log-transformation performed.')
         else:  # mixed positive and negative numbers
-            print('Log-transformation cannot be applied as LCA scores overlap zero.')
+            log.warning('Log-transformation cannot be applied as LCA scores overlap zero.')
 
         # print('Filtering took {} seconds'.format(np.round(time() - start, 2)))
 
@@ -395,7 +396,7 @@ def perform_GSA(self, act_number=0, method_number=0,
         # perform delta analysis
         time_delta = time()
         self.Si = delta.analyze(self.problem, self.X, self.Y, print_to_console=False)
-        print('Delta analysis took {} seconds'.format(np.round(time() - time_delta, 2), ))
+        log.info('Delta analysis took {} seconds'.format(np.round(time() - time_delta, 2), ))
 
         # put GSA results in to dataframe
         self.dfgsa = pd.DataFrame(self.Si, index=self.names).sort_values(by='delta', ascending=False)
@@ -406,7 +407,7 @@ def perform_GSA(self, act_number=0, method_number=0,
         self.df_final.reset_index(inplace=True)
         self.df_final['pedigree'] = [str(x) for x in self.df_final['pedigree']]
 
-        print('GSA took {} seconds'.format(np.round(time() - start, 2)))
+        log.info('GSA took {} seconds'.format(np.round(time() - start, 2)))
 
     def get_save_name(self):
         save_name = self.mc.cs_name + '_' + str(self.mc.iterations) + '_' + self.activity['name'] + \
diff --git a/activity_browser/bwutils/strategies.py b/activity_browser/bwutils/strategies.py
index dc014a4c8..690ff9ae9 100644
--- a/activity_browser/bwutils/strategies.py
+++ b/activity_browser/bwutils/strategies.py
@@ -11,6 +11,13 @@
 
 from .commontasks import clean_activity_name
 from ..bwutils.errors import ExchangeErrorValues
+
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 TECHNOSPHERE_TYPES = {"technosphere", "substitution", "production"}
 BIOSPHERE_TYPES = {"economic", "emission", "natural resource", "social"}
 
@@ -118,7 +125,7 @@ def relink_exchanges(exchanges: list, candidates: dict, duplicates: dict) -> tup
                     # Commit changes every 10k exchanges.
                     transaction.commit()
         except (StrategyError, ValidityError) as e:
-            print(e)
+            log.error(e)
             transaction.rollback()
     return (remainder, altered, unlinked_exchanges)
 
@@ -129,7 +136,7 @@ def relink_exchanges_existing_db(db: bw.Database, old: str, other: bw.Database)
     This means possibly doing a lot of sqlite update calls.
     """
     if old == other.name:
-        print("No point relinking to same database.")
+        log.info("No point relinking to same database.")
         return
     assert db.backend == "sqlite", "Relinking only allowed for SQLITE backends"
     assert other.backend == "sqlite", "Relinking only allowed for SQLITE backends"
@@ -150,7 +157,7 @@ def relink_exchanges_existing_db(db: bw.Database, old: str, other: bw.Database)
     #  this updates the 'depends' in metadata
     (remainder, altered, unlinked_exchanges) = relink_exchanges(exchanges, candidates, duplicates)
     db.process()
-    print(
+    log.info(
         "Relinked database '{}', {} exchange inputs changed from '{}' to '{}'.".format(
             db.name, altered, old, other.name
         )
@@ -160,7 +167,7 @@ def relink_exchanges_existing_db(db: bw.Database, old: str, other: bw.Database)
 
 def relink_activity_exchanges(act, old: str, other: bw.Database) -> tuple:
     if old == other.name:
-        print("No point relinking to same database.")
+        log.info("No point relinking to same database.")
         return
     db = bw.Database(act.key[0])
     assert db.backend == "sqlite", "Relinking only allowed for SQLITE backends"
@@ -179,7 +186,7 @@ def relink_activity_exchanges(act, old: str, other: bw.Database) -> tuple:
 
     (remainder, altered, unlinked_exchanges) = relink_exchanges(exchanges, candidates, duplicates)
     db.process()
-    print(
+    log.info(
         "Relinked database '{}', {} exchange inputs changed from '{}' to '{}'.".format(
             db.name, altered, old, other.name
         )
diff --git a/activity_browser/bwutils/superstructure/excel.py b/activity_browser/bwutils/superstructure/excel.py
index cc7f64524..be98fe1d6 100644
--- a/activity_browser/bwutils/superstructure/excel.py
+++ b/activity_browser/bwutils/superstructure/excel.py
@@ -8,6 +8,12 @@
 
 from .utils import SUPERSTRUCTURE
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 def convert_tuple_str(x):
     try:
@@ -21,7 +27,7 @@ def get_sheet_names(document_path: Union[str, Path]) -> List[str]:
         wb = openpyxl.load_workbook(filename=document_path, read_only=True)
         return wb.sheetnames
     except UnicodeDecodeError as e:
-        print("Given document uses an unknown encoding: {}".format(e))
+        log.error("Given document uses an unknown encoding: {}".format(e))
 
 def get_header_index(document_path: Union[str, Path], import_sheet: int):
     """Retrieves the line index for the column headers, will raise an
diff --git a/activity_browser/bwutils/superstructure/file_imports.py b/activity_browser/bwutils/superstructure/file_imports.py
index af88491db..00d9d7375 100644
--- a/activity_browser/bwutils/superstructure/file_imports.py
+++ b/activity_browser/bwutils/superstructure/file_imports.py
@@ -6,10 +6,16 @@
 
 from typing import Optional, Union
 from ..errors import (
-    ImportCanceledError, ActivityProductionValueError, IncompatibleDatabaseNamingError,
+    ActivityProductionValueError, IncompatibleDatabaseNamingError,
     InvalidSDFEntryValue, ExchangeErrorValues
 )
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class ABPopup(QMessageBox):
     """
@@ -142,7 +148,7 @@ def database_and_key_check(data: pd.DataFrame) -> None:
                     msg = "Error in importing file with activity {} and {}".format(ds[4], ds[5])
                     raise IncompatibleDatabaseNamingError()
         except IncompatibleDatabaseNamingError as e:
-            print(msg)
+            log.error(msg)
             raise e
 
     @staticmethod
@@ -160,7 +166,7 @@ def production_process_check(data: pd.DataFrame, scenario_names: list) -> None:
                 msg = "Error with the production value in the exchange between activity {} and {}".format(failed['from activity name'], failed['to activity name'])
                 raise ActivityProductionValueError()
         except ActivityProductionValueError as e:
-            print(msg)
+            log.error(msg)
             raise e
 
     @staticmethod
@@ -179,7 +185,7 @@ def na_value_check(data: pd.DataFrame, fields: list) -> None:
                 msg = "Error with NA's in the exchange between activity {} and {}".format(hasNA['from activity name'], hasNA['to activity name'])
                 raise InvalidSDFEntryValue()
         except InvalidSDFEntryValue as e:
-            print(msg)
+            log.error(msg)
             raise e
 
     @staticmethod
diff --git a/activity_browser/bwutils/superstructure/manager.py b/activity_browser/bwutils/superstructure/manager.py
index 60f0793fb..7b23417d2 100644
--- a/activity_browser/bwutils/superstructure/manager.py
+++ b/activity_browser/bwutils/superstructure/manager.py
@@ -11,6 +11,12 @@
 from .dataframe import scenario_columns
 from .utils import guess_flow_type, SUPERSTRUCTURE, _time_it_
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 EXCHANGE_KEYS = pd.Index(["from key", "to key"])
 INDEX_KEYS = pd.Index(["from key", "to key", "flow type"])
@@ -163,7 +169,6 @@ def merge_flows_to_self(df: pd.DataFrame) -> pd.DataFrame:
 
             extra_df = pd.DataFrame(list_exc)
             extra_df.index = prod_idxs
-
             extra_df.loc[:, scenario_cols] = extra_df.loc[:, scenario_cols] / (extra_df.loc[:, scenario_cols] + df.loc[tech_idxs, scenario_cols].values)
 
             # drop the 'technosphere' flows
@@ -179,7 +184,7 @@ def remove_duplicates(df: pd.DataFrame) -> pd.DataFrame:
         """
         duplicates = df.index.duplicated(keep="last")
         if duplicates.any():
-            print("Found and dropped {} duplicate exchanges.".format(duplicates.sum()))
+            log.warning("Found and dropped {} duplicate exchanges.".format(duplicates.sum()))
             return df.loc[~duplicates, :]
         return df
 
@@ -198,7 +203,7 @@ def build_index(df: pd.DataFrame) -> pd.MultiIndex:
                                                                                                   len(df))
         unknown_flows = df.loc[:, "flow type"].isna()
         if unknown_flows.any():
-            print("Not all flow types are known, guessing {} flows".format(
+            log.warning("Not all flow types are known, guessing {} flows".format(
                 unknown_flows.sum()
             ))
             df.loc[unknown_flows, "flow type"] = df.loc[
diff --git a/activity_browser/bwutils/superstructure/utils.py b/activity_browser/bwutils/superstructure/utils.py
index 27823e48e..77cec5538 100644
--- a/activity_browser/bwutils/superstructure/utils.py
+++ b/activity_browser/bwutils/superstructure/utils.py
@@ -3,6 +3,12 @@
 import pandas as pd
 import time
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 # Different kinds of indexes, to allow for quick selection of data from
 # the Superstructure DataFrame.
 SUPERSTRUCTURE = pd.Index([
@@ -39,6 +45,6 @@ def _time_it_(func):
     def wrapper(*args):
         now = time.time()
         result = func(*args)
-        print(f"{func} -- " + str(time.time() - now))
+        log.info(f"{func} -- " + str(time.time() - now))
         return result
     return wrapper
\ No newline at end of file
diff --git a/activity_browser/controllers/database.py b/activity_browser/controllers/database.py
index 38f88f71e..1e3068676 100644
--- a/activity_browser/controllers/database.py
+++ b/activity_browser/controllers/database.py
@@ -17,8 +17,16 @@
 from ..signals import signals
 from .project import ProjectController
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
+
 
 class DatabaseController(QObject):
+
     def __init__(self, parent=None):
         super().__init__(parent)
         self.window = parent
@@ -53,7 +61,7 @@ def ensure_sqlite_indices(self):
         @LegacyCode?
         """
         if bw.databases and not sqlite3_lci_db._database.get_indexes('activitydataset'):
-            print("creating missing sqlite indices")
+            log.info("creating missing sqlite indices")
             bw.Database(list(bw.databases)[-1])._add_indices()
 
     @Slot(name="bw2Setup")
diff --git a/activity_browser/controllers/plugin.py b/activity_browser/controllers/plugin.py
index 5abe0b874..d7db65e22 100644
--- a/activity_browser/controllers/plugin.py
+++ b/activity_browser/controllers/plugin.py
@@ -11,6 +11,12 @@
 from ..signals import signals
 from ..settings import project_settings, ab_settings
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class PluginController(QObject):
 
@@ -47,16 +53,15 @@ def discover_plugins(self):
 
     def load_plugin(self, name):
         try:
-            print("Importing plugin {}".format(name))
+            log.info("Importing plugin {}".format(name))
             plugin_lib = importlib.import_module(name)
             importlib.reload(plugin_lib)
             return plugin_lib.Plugin()
-        except:
-            print("Error: Import of plugin {} failed".format(name))
-            print(traceback.format_exc())
+        except Exception as e:
+            log.error("Error: Import of plugin {} failed".format(name), error=e)
 
     def remove_plugin(self, name):
-        print("Removing plugin {}".format(name))
+        log.info("Removing plugin {}".format(name))
         # Apply plugin remove() function
         self.plugins[name].remove()
         # Close plugin tabs
@@ -72,9 +77,9 @@ def add_plugin(self, name, select: bool = True):
             # Add plugins tabs
             for tab in plugin.tabs:
                 self.window.add_tab_to_panel(tab, plugin.infos["name"], tab.panel)
-            print("Loaded tab {}".format(name))
+            log.info("Loaded tab {}".format(name))
             return
-        print("Removing plugin {}".format(name))
+        log.info("Removing plugin {}".format(name))
         # Apply plugin remove() function
         self.plugins[name].remove()
         # Close plugin tabs
@@ -94,7 +99,7 @@ def reload_plugins(self):
             try:
                 self.add_plugin(name)
             except:
-                print(f"Error: plugin {name} not installed")
+                log.error(f"Error: plugin {name} not installed")
 
     def close_plugins(self):
         """ close all plugins
diff --git a/activity_browser/controllers/project.py b/activity_browser/controllers/project.py
index 5a47730ae..40a3bd881 100644
--- a/activity_browser/controllers/project.py
+++ b/activity_browser/controllers/project.py
@@ -8,6 +8,12 @@
 from activity_browser.signals import signals
 from activity_browser.ui.widgets import TupleNameDialog, ProjectDeletionDialog
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class ProjectController(QObject):
     """The controller that handles all of the AB features on the level of
@@ -33,11 +39,11 @@ def switch_brightway2_dir_path(self, dirpath: str) -> None:
 
     def load_settings(self) -> None:
         if ab_settings.settings:
-            print("Loading user settings:")
+            log.info("Loading user settings:")
             self.switch_brightway2_dir_path(dirpath=ab_settings.current_bw_dir)
             self.change_project(ab_settings.startup_project)
-        print('Brightway2 data directory: {}'.format(bw.projects._base_data_dir))
-        print('Brightway2 active project: {}'.format(bw.projects.current))
+        log.info('Brightway2 data directory: {}'.format(bw.projects._base_data_dir))
+        log.info('Brightway2 active project: {}'.format(bw.projects.current))
 
     @staticmethod
     @Slot(str, name="changeProject")
@@ -48,13 +54,13 @@ def change_project(name: str, reload: bool = False) -> None:
 #        assert name, "No project name given."
         name = "default" if not name else name
         if name not in bw.projects:
-            print("Project does not exist: {}, creating!".format(name))
+            log.info("Project does not exist: {}, creating!".format(name))
             bw.projects.create_project(name)
 
         if name != bw.projects.current or reload:
             bw.projects.set_current(name)
         signals.project_selected.emit()
-        print("Loaded project:", name)
+        log.info("Loaded project:", name)
 
     @Slot(name="createProject")
     def new_project(self, name=None):
@@ -141,7 +147,7 @@ def new_calculation_setup(self) -> None:
                 return
             bw.calculation_setups[name] = {'inv': [], 'ia': []}
             signals.calculation_setup_selected.emit(name)
-            print("New calculation setup: {}".format(name))
+            log.info("New calculation setup: {}".format(name))
 
     @Slot(str, name="copyCalculationSetup")
     def copy_calculation_setup(self, current: str) -> None:
@@ -155,13 +161,13 @@ def copy_calculation_setup(self, current: str) -> None:
                 return
             bw.calculation_setups[new_name] = bw.calculation_setups[current].copy()
             signals.calculation_setup_selected.emit(new_name)
-            print("Copied calculation setup {} as {}".format(current, new_name))
+            log.info("Copied calculation setup {} as {}".format(current, new_name))
 
     @Slot(str, name="deleteCalculationSetup")
     def delete_calculation_setup(self, name: str) -> None:
         del bw.calculation_setups[name]
         signals.set_default_calculation_setup.emit()
-        print("Deleted calculation setup: {}".format(name))
+        log.info("Deleted calculation setup: {}".format(name))
 
     @Slot(str, name="renameCalculationSetup")
     def rename_calculation_setup(self, current: str) -> None:
@@ -174,11 +180,9 @@ def rename_calculation_setup(self, current: str) -> None:
             if not self._can_use_cs_name(new_name):
                 return
             bw.calculation_setups[new_name] = bw.calculation_setups[current].copy()
-            # print("Current setups:", list(bw.calculation_setups.keys()))
             del bw.calculation_setups[current]
-            # print("After deletion of {}:".format(current), list(bw.calculation_setups.keys()))
             signals.calculation_setup_selected.emit(new_name)
-            print("Renamed calculation setup from {} to {}".format(current, new_name))
+            log.info("Renamed calculation setup from {} to {}".format(current, new_name))
 
     def _can_use_cs_name(self, new_name: str) -> bool:
         if new_name in bw.calculation_setups.keys():
@@ -223,17 +227,17 @@ def copy_method(self, method: tuple, level: str = None) -> None:
                     QtWidgets.QMessageBox.warning(self.window, "Copy failed", warn)
                     return
                 mthd.copy(new_method)
-                print("Copied method {} into {}".format(str(mthd.name), str(new_method)))
+                log.info("Copied method {} into {}".format(str(mthd.name), str(new_method)))
             signals.new_method.emit()
 
     @Slot(tuple, name="deleteMethod")
-    def delete_method(self, method: tuple, level:str = None) -> None:
+    def delete_method(self, method_: tuple, level:str = None) -> None:
         """Call delete on the (first) selected method and present confirmation dialog."""
         if level is not None and level != 'leaf':
-            methods = [bw.Method(mthd) for mthd in bw.methods if set(method).issubset(mthd)]
+            methods = [bw.Method(mthd) for mthd in bw.methods if set(method_).issubset(mthd)]
         else:
-            methods = [bw.Method(method)]
-        method = bw.Method(method)
+            methods = [bw.Method(method_)]
+        method = bw.Method(method_)
         dialog = QtWidgets.QMessageBox()
         dialog.setWindowTitle("Are you sure you want to delete this method?")
         dialog.setText("You are about to PERMANENTLY delete the following Impact Category:\n("
@@ -245,8 +249,7 @@ def delete_method(self, method: tuple, level:str = None) -> None:
         if dialog.exec_() == QtWidgets.QMessageBox.Yes:
             for mthd in methods:
                 mthd.deregister()
-                print("Deleted method {}".format(str(mthd.name)))
-            # TODO: ensure the method no longer shows up anywhere.
+                log.info("Deleted method {}".format(str(mthd.name)))
             signals.method_deleted.emit()
 
     @Slot(list, tuple, name="removeCFUncertainty")
@@ -318,7 +321,6 @@ def delete_method_from_cf(self, to_delete: tuple, method: tuple):
             for d in to_delete:
                 if i[0][0] == d[0][0] and i[0][1] == d[0][1]:
                     delete_list.append(i)
-                    print('yep same')
         for d in delete_list:
             cfs.remove(d)
         method.write(cfs)
diff --git a/activity_browser/layouts/panels/panel.py b/activity_browser/layouts/panels/panel.py
index afd5c5a38..40e5bbb20 100644
--- a/activity_browser/layouts/panels/panel.py
+++ b/activity_browser/layouts/panels/panel.py
@@ -3,6 +3,12 @@
 
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class ABTab(QtWidgets.QTabWidget):
     def __init__(self, parent=None):
@@ -45,7 +51,7 @@ def hide_tab(self, tab_name, current_index=0):
         if tab_name in self.tabs:
             tab = self.tabs[tab_name]
             if self.indexOf(tab) != -1:
-                print("-hiding tab:", tab_name)
+                log.info("-hiding tab:", tab_name)
                 tab.setVisible(False)
                 # Only explicitly alter the tab index if we're hiding the
                 # current tab itself.
@@ -57,7 +63,7 @@ def show_tab(self, tab_name):
         """Makes existing tab visible."""
         if tab_name in self.tabs:
             tab = self.tabs[tab_name]
-            print("+showing tab:", tab_name)
+            log.info("+showing tab:", tab_name)
             tab.setVisible(True)
             self.addTab(tab, tab_name)
             self.select_tab(tab)
@@ -68,7 +74,7 @@ def get_tab_name(self, obj):
         if len(tab_names) == 1:
             return tab_names[0]
         else:
-            print("Warning: found", len(tab_names), "occurences of this object.")
+            log.warning("found", len(tab_names), "occurences of this object.")
 
     def get_tab_name_from_index(self, index):
         """Return the name of a tab based on its index."""
@@ -80,11 +86,8 @@ def get_tab_name_from_index(self, index):
 
     def hide_when_empty(self):
         """Show tab if it has sub-tabs (not empty) or hide if it has no sub-tabs (empty)."""
-        # print("\nChecking for empty tabs:")
         for tab_name, tab in self.tabs.items():
-            # print("Tab:", self.get_tab_name(tab), "...")
             if hasattr(tab, "tabs"):
-                # print("Subtabs:", tab.tabs.keys())
                 if not tab.tabs:
                     self.hide_tab(tab_name)
                 # else:  # leads to strange behaviour of setCurrentIndex/select_tab
@@ -94,7 +97,6 @@ def close_tab(self, index):
         """Close tab by index."""
         widget = self.widget(index)
         tab_name = self.get_tab_name(widget)
-        # print("Closing tab:", tab_name)
         if widget in self.tabs.values():
             del self.tabs[tab_name]
             widget.deleteLater()
diff --git a/activity_browser/layouts/panels/right.py b/activity_browser/layouts/panels/right.py
index 7b14bc951..0d1279d7b 100644
--- a/activity_browser/layouts/panels/right.py
+++ b/activity_browser/layouts/panels/right.py
@@ -16,6 +16,12 @@
 from ...bwutils.commontasks import get_activity_name
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class RightPanel(ABTab):
     side = "right"
@@ -49,7 +55,7 @@ def show_tab(self, tab_name):
         """
         if tab_name in self.tabs:
             tab = self.tabs[tab_name]
-            print("+showing tab:", tab_name)
+            log.info("+showing tab:", tab_name)
             tab.setVisible(True)
             self.insertTab(self.tab_order[tab_name], tab, tab_name)
             self.select_tab(tab)
@@ -77,7 +83,7 @@ def connect_signals(self):
     def add_tab(self, key, select=True):
         """Opens new tab or focuses on already open one."""
         if key not in self.tabs:
-            print("adding graph tab")
+            log.info("adding graph tab")
             new_tab = GraphNavigatorWidget(self, key=key)
             self.tabs[key] = new_tab
             self.addTab(new_tab, get_activity_name(bw.get_activity(key), str_length=30))
diff --git a/activity_browser/layouts/tabs/LCA_results_tab.py b/activity_browser/layouts/tabs/LCA_results_tab.py
index 51755bd77..cdf929fcf 100644
--- a/activity_browser/layouts/tabs/LCA_results_tab.py
+++ b/activity_browser/layouts/tabs/LCA_results_tab.py
@@ -10,6 +10,12 @@
 from ...signals import signals
 from ...bwutils.errors import ABError
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class LCAResultsTab(ABTab):
     """Tab that contains subtabs for each calculation setup."""
@@ -61,7 +67,7 @@ def generate_setup(self, data: dict):
             signals.show_tab.emit("LCA results")
         except BW2CalcError as e:
             initial, *other = e.args
-            print(traceback.format_exc())
+            log.error(traceback.format_exc())
             msg = QMessageBox(
                 QMessageBox.Warning, "Calculation problem", str(initial),
                 QMessageBox.Ok, self
diff --git a/activity_browser/layouts/tabs/LCA_results_tabs.py b/activity_browser/layouts/tabs/LCA_results_tabs.py
index 399735caf..1bdac5070 100644
--- a/activity_browser/layouts/tabs/LCA_results_tabs.py
+++ b/activity_browser/layouts/tabs/LCA_results_tabs.py
@@ -36,6 +36,13 @@
 from ...ui.web import SankeyNavigatorWidget
 from .base import BaseRightTab
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
+
 def get_header_layout(header_text: str) -> QVBoxLayout:
     vlayout = QVBoxLayout()
     vlayout.addWidget(header(header_text))
@@ -160,7 +167,7 @@ def update_scenario_data(self, index: int) -> None:
     def generate_content_on_click(self, index):
         if index == self.indexOf(self.tabs.sankey):
             if not self.tabs.sankey.has_sankey:
-                print('Generating Sankey Tab')
+                log.info('Generating Sankey Tab')
                 self.tabs.sankey.new_sankey()
 
     @QtCore.Slot(name="lciaScenarioExport")
@@ -1218,11 +1225,11 @@ def calculate_mc_lca(self):
         iterations = int(self.iterations.text())
         seed = None
         if self.seed.text():
-            print('SEED: ', self.seed.text())
+            log.info('SEED: ', self.seed.text())
             try:
                 seed = int(self.seed.text())
-            except ValueError:
-                traceback.print_exc()
+            except ValueError as e:
+                log.error('Seed value must be an integer number or left empty.', error=e)
                 QMessageBox.warning(self, 'Warning', 'Seed value must be an integer number or left empty.')
                 self.seed.setText('')
                 return
@@ -1240,7 +1247,7 @@ def calculate_mc_lca(self):
             self.update_mc()
         except InvalidParamsError as e:  # This can occur if uncertainty data is missing or otherwise broken
             # print(e)
-            traceback.print_exc()
+            log.error(error=e)
             QMessageBox.warning(self, 'Could not perform Monte Carlo simulation', str(e))
         QApplication.restoreOverrideCursor()
 
@@ -1490,7 +1497,7 @@ def calculate_gsa(self):
                                  cutoff_technosphere=cutoff_technosphere, cutoff_biosphere=cutoff_biosphere)
             # self.update_mc()
         except Exception as e:  # Catch any error...
-            traceback.print_exc()
+            log.error(error=e)
             message = str(e)
             message_addition = ''
             if message == 'singular matrix':
@@ -1516,7 +1523,7 @@ def update_gsa(self, cs_name=None):
         self.table.table_name = 'gsa_output_' + self.GSA.get_save_name()
 
         if self.checkbox_export_data_automatically.isChecked():
-            print("EXPORTING DATA")
+            log.info("EXPORTING DATA")
             self.GSA.export_GSA_input()
             self.GSA.export_GSA_output()
 
@@ -1556,15 +1563,18 @@ class MonteCarloWorkerThread(QtCore.QThread):
     Unfortunately, pyparadiso does not allow parallel calculations on Windows (crashes).
     So this is for future reference in case this issue is solved... """
 
+    def __init__(self):
+        pass
+
     def set_mc(self, mc, iterations=20):
         self.mc = mc
         self.iterations = iterations
 
     def run(self):
-        print('Starting new Worker Thread. Iterations:', self.iterations)
+        log.info('Starting new Worker Thread. Iterations:', self.iterations)
         self.mc.calculate(iterations=self.iterations)
         # res = bw.GraphTraversal().calculate(self.demand, self.method, self.cutoff, self.max_calc)
-        print('in thread {}'.format(QtCore.QThread.currentThread()))
+        log.info('in thread {}'.format(QtCore.QThread.currentThread()))
         signals.monte_carlo_ready.emit(self.mc.cs_name)
 
 
diff --git a/activity_browser/layouts/tabs/LCA_setup.py b/activity_browser/layouts/tabs/LCA_setup.py
index 3acd4a071..03259f7d1 100644
--- a/activity_browser/layouts/tabs/LCA_setup.py
+++ b/activity_browser/layouts/tabs/LCA_setup.py
@@ -20,6 +20,12 @@
 from ...ui.widgets import ExcelReadDialog
 from .base import BaseRightTab
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 """
 Lifecycle of a calculation setup
 ================================
@@ -456,9 +462,9 @@ def load_action(self) -> None:
             idx = dialog.import_sheet.currentIndex()
             file_type_suffix = dialog.path.suffix
             separator = dialog.field_separator.currentData()
-            print("separator == '{}'".format(separator))
+            log.info("separator == '{}'".format(separator))
             QtWidgets.QApplication.setOverrideCursor(Qt.WaitCursor)
-            print('Loading Scenario file. This may take a while for large files')
+            log.info('Loading Scenario file. This may take a while for large files')
             try:
                 # Try and read as a superstructure file
                 if file_type_suffix == ".feather":
@@ -477,7 +483,7 @@ def load_action(self) -> None:
                 self.sync_superstructure(df)
             except (IndexError, ValueError) as e:
                 # Try and read as parameter scenario file.
-                print("Superstructure: {}\nAttempting to read as parameter scenario file.".format(e))
+                log.error("Superstructure: {}\nAttempting to read as parameter scenario file.".format(e))
                 df = pd.read_excel(path, sheet_name=idx, engine="openpyxl")
                 include_default = True
                 if "default" not in df.columns:
@@ -508,5 +514,5 @@ def sync_superstructure(self, df: pd.DataFrame) -> None:
     @property
     def dataframe(self) -> pd.DataFrame:
         if self.scenario_df.empty:
-            print("No data in scenario table {}, skipping".format(self.index + 1))
+            log.warning("No data in scenario table {}, skipping".format(self.index + 1))
         return self.scenario_df
diff --git a/activity_browser/layouts/tabs/debug.py b/activity_browser/layouts/tabs/debug.py
index e2713b895..443e89bcf 100644
--- a/activity_browser/layouts/tabs/debug.py
+++ b/activity_browser/layouts/tabs/debug.py
@@ -1,9 +1,10 @@
-from PySide2 import QtWidgets
+from PySide2 import QtWidgets, QtCore
 import sys
 
 from ..panels import ABTab
 from ...ui.style import header
 from ...ui.utils import StdRedirector
+from ...signals import signals
 
 
 class DebugTab(ABTab):
@@ -11,9 +12,9 @@ class DebugTab(ABTab):
     def __init__(self, parent = None):
         super(DebugTab, self).__init__(parent)
 
-        self.log = QtWidgets.QTextEdit(self)
-        sys.stdout = StdRedirector(self.log, sys.stdout, None)
-        sys.stderr = StdRedirector(self.log, sys.stderr, "blue")
+        self.log = QtWidgets.QPlainTextEdit(self)
+        sys.stdout = StdRedirector(self.log, sys.stdout)
+        sys.stderr = StdRedirector(self.log, sys.stderr)
 
         self.debug_display = QtWidgets.QVBoxLayout()
         self.title = header('Program debugger output:')
@@ -23,3 +24,10 @@ def __init__(self, parent = None):
 
         self.setLayout(self.debug_display)
         self.setVisible(False)
+
+        signals.log.connect(self.write_log_message)
+
+    @QtCore.Slot(name="writeLogMessage")
+    def write_log_message(self, msg: str):
+        self.log.appendPlainText(msg)
+        self.log.centerCursor()
\ No newline at end of file
diff --git a/activity_browser/layouts/tabs/impact_categories.py b/activity_browser/layouts/tabs/impact_categories.py
index 7d497192f..8f751e3f9 100644
--- a/activity_browser/layouts/tabs/impact_categories.py
+++ b/activity_browser/layouts/tabs/impact_categories.py
@@ -57,7 +57,6 @@ def cf_read_only_changed(self, editable: bool) -> None:
             self.cf_table.setEditTriggers(QtWidgets.QTableView.DoubleClicked)
         else:
             self.cf_table.setEditTriggers(QtWidgets.QTableView.NoEditTriggers)
-        print(self.read_only)
 
 class MethodsTab(QtWidgets.QWidget):
     def __init__(self, parent):
diff --git a/activity_browser/logger.py b/activity_browser/logger.py
new file mode 100644
index 000000000..b413bfe38
--- /dev/null
+++ b/activity_browser/logger.py
@@ -0,0 +1,173 @@
+from PySide2.QtCore import Slot
+import logging
+import os, time, appdirs
+import random, string
+
+from .signals import signals
+
+
+class ABHandler(object):
+    """
+    Creates two logging streams, one to the console (with >=INFORMATION logs)
+    the second to a file specified with the name argument (with >=WARNING logs)
+    and attaches these to a logger created in the calling modules.
+
+    Provides the formats and initialization procedures for the logging streams.
+    """
+    log = None
+    file_path = None
+    stream_handler = None
+    file_handler = None
+    qt_handler = None
+
+    def __init__(self, name: str = None):
+        self.module_name = name
+
+    @staticmethod
+    def initialize_with_logger(logger: logging.Logger):
+        """
+        Will initialize the handlers for the logging streams and check that the file handler
+        is properly setup before linking to the passed Logger object.
+
+        Parameters
+        ----------
+        logger: an object of type logging.Logger obtained in the calling module with getLogger()
+        """
+        name = logger.name + ABHandler.timestamp() + '.log'
+        dir_path = appdirs.user_log_dir('ActivityBrowser', 'ActivityBrowser')
+        os.makedirs(dir_path, exist_ok=True)
+        ABHandler.clean_directory(dir_path)
+        ABHandler.file_path = dir_path + "/" + name
+        ABHandler.stream_handler = logging.StreamHandler()
+        ABHandler.file_handler = logging.FileHandler(ABHandler.file_path)
+
+        log_format = logging.Formatter("%(asctime)s - %(levelname)s - %(ABmodule)s - %(message)s - ")
+
+        console_format = logging.Formatter("%(message)s")
+        ABHandler.stream_handler.setFormatter(console_format)
+        ABHandler.file_handler.setFormatter(log_format)
+
+        ABHandler.stream_handler.setLevel(logging.INFO)
+        ABHandler.file_handler.setLevel(logging.DEBUG)
+
+        ABHandler.qt_handler = ABLogHandler()
+        ABHandler.qt_handler.setFormatter(console_format)
+
+        return ABHandler.setup_with_logger(logger)
+
+    @classmethod
+    def setup_with_logger(cls, logger: logging.Logger = None, module: str = None):
+        """
+        Links the logger object to the different stream handlers. This avoids the process of
+        creating new handlers and should be the general method to call for linking the
+        logging.Logger objects.
+
+        Parameters
+        ----------
+        logger: an object of type logging.Logger requiring setup with logging.Handlers
+        """
+
+        ABHandler.log = logger
+        assert ABHandler.log is not None
+
+        ABHandler.log.addHandler(ABHandler.stream_handler)
+        ABHandler.log.addHandler(ABHandler.file_handler)
+        ABHandler.log.addHandler(ABHandler.qt_handler)
+        ABHandler.log.setLevel(logging.INFO)
+
+        if module is not None:
+            return ABHandler(module)
+        return ABHandler("root")
+
+    @staticmethod
+    def unique_string(n: int) -> str:
+        """Returns a random string of length n, to avoid issues with non-unique log files"""
+        return ''.join(random.choice(string.ascii_letters) for i in range(n))
+
+    @staticmethod
+    def timestamp() -> str:
+        """Returns a timestamped string, the format provided is:
+        day of the month _ month _ year - hour _ minute _ second"""
+        stmp = time.localtime()
+        return f"-{stmp.tm_mday}_{stmp.tm_mon}_{stmp.tm_year}-{stmp.tm_hour}_{stmp.tm_min}_{stmp.tm_sec}"
+
+    @staticmethod
+    def clean_directory(dirpath: str) -> None:
+        """Cleans the Activity-Browser/log directory of all files older than 365 days"""
+        time_limit = time.time() - 24*3600*365
+        for file in os.listdir(dirpath):
+            filepath = dirpath + '/' + file
+            if os.stat(filepath).st_mtime < time_limit:
+                os.remove(filepath)
+
+    def log_file_path(self):
+        return ABHandler.file_path
+
+    def message(self, *args) -> str:
+        _str = ''
+        for arg in args:
+            if not isinstance(arg, str):
+                _str += str(arg)
+            else:
+                _str += arg
+        return _str
+
+    def debug(self, msg: str, *args) -> None:
+        ABHandler.log.debug(self.message(msg, *args), extra={'ABmodule': self.module_name})
+
+    def info(self, msg: str, *args) -> None:
+        ABHandler.log.info(self.message(msg, *args), extra={'ABmodule': self.module_name})
+
+    def warning(self, msg: str, *args) -> None:
+        ABHandler.log.warning(self.message(msg, *args), extra={'ABmodule': self.module_name})
+
+    def error(self, msg: str = None, *args, **kwargs) -> None:
+        """ Provides a wrapper for the Logger.error method. This is to keep the logging messages
+        consistent with previous practices. Exception handling is provided through the use of
+        kwargs
+        Parameters:
+            msg, *args: strings that form the logging message, multiple strings allowed
+            **kwargs: provided for the handling of stack traces, the two arguments taken here are:
+                error=''
+                exc_info=bool
+        """
+        if msg is not None:
+            ABHandler.log.error(self.message(msg, *args), extra={'ABmodule': self.module_name})
+
+        exc_info = True # TODO Move this error handling with the use of kwargs into a single error message
+        if kwargs and 'error' in kwargs:
+            if 'exc_info' in kwargs:
+                exc_info = kwargs['exc_info']
+            ABHandler.log.error(kwargs['error'], exc_info=exc_info)
+
+    def addHandler(self, handler) -> None:
+        ABHandler.log.addHandler(handler)
+
+    def setLevel(self, level, root: bool = False) -> None:
+        if root:
+            ABHandler.log.root.setLevel(level)
+        else:
+            ABHandler.log.setLevel(level)
+
+
+class ABLogHandler(logging.Handler):
+    """Customizing a handler for running within a separate thread, emitting logs to the main
+    thread."""
+    def __init__(self):
+        super().__init__()
+        self.setLevel(logging.INFO)
+
+    def emit(self, record):
+        msg = self.format(record)
+        signals.log.emit(msg)
+
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.initialize_with_logger(logger)
+
+#handler = ABLogHandler()
+#handler.setFormatter(logging.Formatter("%(module)s - %(levelname)s - %(asctime)s - %(message)s"))
+#log = ABHandler('ab_logs')
+#log.addHandler(handler)
+#log.propagate = True
+#logging.setLoggerClass(ABHandler)
diff --git a/activity_browser/settings.py b/activity_browser/settings.py
index 85b34d878..29248a688 100644
--- a/activity_browser/settings.py
+++ b/activity_browser/settings.py
@@ -10,11 +10,17 @@
 import brightway2 as bw
 
 from .signals import signals
+import logging
+from .logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
 
 
 class BaseSettings(object):
     """ Base Class for handling JSON settings files.
     """
+
     def __init__(self, directory: str, filename: str = None):
         self.data_dir = directory
         self.filename = filename or "default_settings.json"
@@ -236,7 +242,7 @@ def reset_for_project_selection(self) -> None:
         """ On switching project, attempt to read the settings for the new
         project.
         """
-        print("Reset project settings directory to:", bw.projects.dir)
+        log.info("Reset project settings directory to:", bw.projects.dir)
         self.settings_file = os.path.join(bw.projects.dir, self.filename)
         self.initialize_settings()
         # create a plugins_list entry for old projects
diff --git a/activity_browser/signals.py b/activity_browser/signals.py
index 9c6ed76ca..f57574406 100644
--- a/activity_browser/signals.py
+++ b/activity_browser/signals.py
@@ -7,6 +7,7 @@ class Signals(QObject):
     While arguments can be passed to signals, it is good practice not to do this if possible. """
 
     # General Settings
+    log = Signal(str)
 
     # bw2 directory
     switch_bw2_dir_path = Signal(str)
diff --git a/activity_browser/ui/figures.py b/activity_browser/ui/figures.py
index a00f84ad1..d1eeb0f23 100644
--- a/activity_browser/ui/figures.py
+++ b/activity_browser/ui/figures.py
@@ -13,6 +13,12 @@
 from activity_browser.utils import savefilepath
 from ..bwutils.commontasks import wrap_text
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 # todo: sizing of the figures needs to be improved and systematized...
 # todo: Bokeh is a potential alternative as it allows interactive visualizations,
@@ -278,7 +284,7 @@ def plot(self, data: np.ndarray, mean: float, label: str = "Value"):
         try:
             sns.histplot(data.T, kde=True, stat="density", ax=self.ax, edgecolor="none")
         except RuntimeError as e:
-            print("Runtime error: {}\nPlotting without KDE.".format(e))
+            log.error("{}: Plotting without KDE.".format(e))
             sns.histplot(data.T, kde=False, stat="density", ax=self.ax, edgecolor="none")
         self.ax.set_xlabel(label)
         self.ax.set_ylabel("Probability density")
diff --git a/activity_browser/ui/statusbar.py b/activity_browser/ui/statusbar.py
index 210ea64a0..e40743c78 100644
--- a/activity_browser/ui/statusbar.py
+++ b/activity_browser/ui/statusbar.py
@@ -6,6 +6,11 @@
 
 from ..signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
 
 class Statusbar(QStatusBar):
     def __init__(self, window):
@@ -27,7 +32,7 @@ def connect_signals(self):
 
     @Slot(str, name="statusLeft")
     def left(self, message: str) -> None:
-        print(message)  # for console output
+        log.info(message)  # for console output
         if isinstance(message, str):
             self.status_message_left.setText(message)
 
diff --git a/activity_browser/ui/tables/LCA_setup.py b/activity_browser/ui/tables/LCA_setup.py
index cc0f4321d..d2a4dc488 100644
--- a/activity_browser/ui/tables/LCA_setup.py
+++ b/activity_browser/ui/tables/LCA_setup.py
@@ -10,6 +10,11 @@
 from .models import CSMethodsModel, CSActivityModel, ScenarioImportModel
 from .views import ABDataFrameView
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
 
 class CSList(QtWidgets.QComboBox):
     def __init__(self, parent=None):
@@ -128,7 +133,7 @@ def dropEvent(self, event):
         event.accept()
         source = event.source()
         if getattr(event.source(), "technosphere", False):
-            print('Dropevent from:', source)
+            log.info('Dropevent from:', source)
             self.model.include_activities(
                 {source.get_key(p): 1.0} for p in source.selectedIndexes()
             )
@@ -152,6 +157,7 @@ def __init__(self, parent=None):
                         "Click and drag to re-order individual rows of the table\n"
                         "Hold CTRL and click to select multiple rows to open or delete them.")
 
+
     @Slot(name="resizeView")
     def custom_view_sizing(self):
         self.setColumnHidden(3, True)
diff --git a/activity_browser/ui/tables/models/activity.py b/activity_browser/ui/tables/models/activity.py
index 8232acc35..97a640fa9 100644
--- a/activity_browser/ui/tables/models/activity.py
+++ b/activity_browser/ui/tables/models/activity.py
@@ -16,6 +16,12 @@
 from activity_browser.signals import signals
 from .base import EditablePandasModel
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class BaseExchangeModel(EditablePandasModel):
     COLUMNS = []
@@ -59,7 +65,7 @@ def create_row(self, exchange) -> dict:
             return row
         except DoesNotExist as e:
             # The input activity does not exist. remove the exchange.
-            print("Broken exchange: {}, removing.".format(e))
+            log.info("Broken exchange: {}, removing.".format(e))
             signals.exchanges_deleted.emit([exchange])
 
     def get_exchange(self, proxy: QModelIndex) -> ExchangeProxyBase:
@@ -118,7 +124,6 @@ def copy_exchanges_for_SDF(self, proxies: list) -> None:
                 continue  # exact duplicate entry into clipboard
             prev = e
             exchanges.append(e)
-            print(exchanges)
         data = bc.get_exchanges_in_scenario_difference_file_notation(exchanges)
         df = pd.DataFrame(data)
         df.to_clipboard(excel=True, index=False)
@@ -200,7 +205,7 @@ def get_interpreter(self) -> Interpreter:
         if act:
             interpreter.symtable.update(ActivityParameter.static(act.group, full=True))
         else:
-            print("No parameter found for {}, creating one on formula save".format(self.key))
+            log.info("No parameter found for {}, creating one on formula save".format(self.key))
             interpreter.symtable.update(ProjectParameter.static())
             interpreter.symtable.update(DatabaseParameter.static(self.key[0]))
         return interpreter
@@ -255,7 +260,7 @@ def create_row(self, exchange: ExchangeProxyBase) -> dict:
             })
             return row
         except DoesNotExist as e:
-            print("Exchange was deleted, continue.")
+            log.info("Exchange was deleted, continue.")
             return {}
 
 
@@ -297,7 +302,7 @@ def create_row(self, exchange) -> dict:
             })
             return row
         except DoesNotExist as e:
-            print("Exchange was deleted, continue.")
+            log.info("Exchange was deleted, continue.")
             return {}
 
 
diff --git a/activity_browser/ui/tables/models/base.py b/activity_browser/ui/tables/models/base.py
index 9659042da..e2b321d90 100644
--- a/activity_browser/ui/tables/models/base.py
+++ b/activity_browser/ui/tables/models/base.py
@@ -11,6 +11,12 @@
 from activity_browser.bwutils import commontasks as bc
 from activity_browser.ui.style import style_item
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class PandasModel(QAbstractTableModel):
     """ Abstract pandas table model adapted from
@@ -30,10 +36,10 @@ def __init__(self, df: pd.DataFrame = None, parent=None):
         self.different_column_types = {}
 
     def rowCount(self, parent=None, *args, **kwargs):
-        return self._dataframe.shape[0]
+        return 0 if self._dataframe is None else self._dataframe.shape[0]
 
     def columnCount(self, parent=None, *args, **kwargs):
-        return self._dataframe.shape[1]
+        return 0 if self._dataframe is None else self._dataframe.shape[1]
 
     def data(self, index, role=Qt.DisplayRole):
         if not index.isValid():
@@ -130,7 +136,7 @@ def test_query_on_column(self, test_type: str, col_data: pd.Series, query) -> pd
             return (float(query[0]) <= col_data.astype(float)) \
                    & (col_data.astype(float) <= float(query[1]))
         else:
-            print("WARNING: unknown filter type >{}<, assuming 'EQUALS'".format(test_type))
+            log.warning("unknown filter type >{}<, assuming 'EQUALS'".format(test_type))
             return col_data == query
 
     def get_filter_mask(self, filters: dict) -> pd.Series:
@@ -170,7 +176,7 @@ def get_filter_mask(self, filters: dict) -> pd.Series:
                 new_mask = self.test_query_on_column(filt_type, col_data_, query)
                 if not any(new_mask):
                     # no matches for this mask, let user know:
-                    print("There were no matches for filter: {}: '{}'".format(col_filt[0], col_filt[1]))
+                    log.info("There were no matches for filter: {}: '{}'".format(col_filt[0], col_filt[1]))
 
                 # create or combine new mask within column
                 if isinstance(col_mask, pd.Series) and col_mode == 'AND':
diff --git a/activity_browser/ui/tables/models/impact_categories.py b/activity_browser/ui/tables/models/impact_categories.py
index c004d9418..594210db6 100644
--- a/activity_browser/ui/tables/models/impact_categories.py
+++ b/activity_browser/ui/tables/models/impact_categories.py
@@ -14,6 +14,12 @@
 from ...wizards import UncertaintyWizard
 from .base import EditablePandasModel, DragPandasModel, TreeItem, BaseTreeModel
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class MethodsListModel(DragPandasModel):
     HEADERS = ["Name", "Unit", "# CFs", "method"]
@@ -370,7 +376,6 @@ def remove_uncertainty(self, proxy_indexes: Iterator[QModelIndex]) -> None:
     @Slot(list, name="deleteCF")
     def delete_cf(self, proxy_indexes: Iterator[QModelIndex]) -> None:
         to_delete = [self.get_cf(p) for p in proxy_indexes]
-        print(to_delete)
         confirm = QMessageBox()
         confirm.setIcon(QMessageBox.Warning)
         confirm.setWindowTitle("Confirm deletion")
@@ -378,7 +383,7 @@ def delete_cf(self, proxy_indexes: Iterator[QModelIndex]) -> None:
         confirm.setStandardButtons(QMessageBox.Ok | QMessageBox.Cancel)
         confirmed = confirm.exec()
         if confirmed == QMessageBox.Ok:
-            print("Deleting CF(s):", to_delete)
+            log.info("Deleting CF(s):", to_delete)
             signals.delete_cf_method.emit(to_delete, self.method.name)
 
     @Slot(tuple, object, name="modifyCf")
diff --git a/activity_browser/ui/tables/models/inventory.py b/activity_browser/ui/tables/models/inventory.py
index 6e672aeb9..1b72c2996 100644
--- a/activity_browser/ui/tables/models/inventory.py
+++ b/activity_browser/ui/tables/models/inventory.py
@@ -15,6 +15,12 @@
 from activity_browser.signals import signals
 from .base import PandasModel, DragPandasModel
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class DatabasesModel(PandasModel):
     HEADERS = ["Name", "Records", "Read-only", "Depends", "Modified"]
@@ -99,7 +105,7 @@ def df_from_metadata(self, db_name: str) -> pd.DataFrame:
     def sync(self, db_name: str, df: pd.DataFrame = None) -> None:
         if df is not None:
             # skip the rest of the sync here if a dataframe is directly supplied
-            print("Pandas Dataframe passed to sync.", df.shape)
+            log.info("Pandas Dataframe passed to sync.", df.shape)
             self._dataframe = df
             self.updated.emit()
             return
diff --git a/activity_browser/ui/tables/models/lca_setup.py b/activity_browser/ui/tables/models/lca_setup.py
index aab6e885b..dac356af2 100644
--- a/activity_browser/ui/tables/models/lca_setup.py
+++ b/activity_browser/ui/tables/models/lca_setup.py
@@ -11,6 +11,12 @@
 from activity_browser.signals import signals
 from .base import EditablePandasModel, PandasModel
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class CSGenericModel(EditablePandasModel):
     """ Intermediate class to enable internal move functionality for the
@@ -130,7 +136,7 @@ def build_row(self, key: tuple, amount: float = 1.0) -> dict:
             row.update({"Amount": amount, "key": key})
             return row
         except (TypeError, ActivityDataset.DoesNotExist):
-            print("Could not load key in Calculation Setup: ", key)
+            log.error("Could not load key '{}' in Calculation Setup '{}'".format(str(key), self.current_cs))
             return {}
 
     @Slot(name="deleteRows")
@@ -159,11 +165,36 @@ class CSMethodsModel(CSGenericModel):
     def __init__(self, parent=None):
         super().__init__(parent=parent)
         self.current_cs = None
-        signals.calculation_setup_selected.connect(self.sync)
+        signals.calculation_setup_selected.connect(self.update_cs)
+        signals.method_deleted.connect(
+            lambda: self.update_cs(self.current_cs))
 
     @property
     def methods(self) -> list:
-        return self._dataframe.loc[:, "method"].to_list()
+        return [] if self._dataframe is None else self._dataframe.loc[:, "method"].to_list()
+
+    @Slot(name="UpdateBWCalculationSetup")
+    def update_cs(self, name: str = None) -> None:
+        """Updates and syncs the bw.calculation_setups for the Impact categories. Removes any
+        Impact category from a calculation setup if it is not present in the current environment"""
+        def filter_methods(cs):
+            """Filters any methods out from the calculation setup if they aren't in bw.methods"""
+            i = 0
+            while i < len(cs):
+                if cs[i] not in bw.methods:
+                    cs.pop(i)
+                else:
+                    i += 1
+            ######## END OF FUNCTION
+
+        if self.current_cs is not None or name is not None:
+            self.current_cs = name
+            filter_methods(bw.calculation_setups[self.current_cs].get('ia', []))
+            self.sync(self.current_cs)
+        else:
+            for name, cs in bw.calculation_setups.items():
+                filter_methods(cs['ia'])
+            self.sync()
 
     @Slot(str, name="syncModel")
     def sync(self, name: str = None) -> None:
diff --git a/activity_browser/ui/tables/models/parameters.py b/activity_browser/ui/tables/models/parameters.py
index 75301f0a2..715516db3 100644
--- a/activity_browser/ui/tables/models/parameters.py
+++ b/activity_browser/ui/tables/models/parameters.py
@@ -15,6 +15,12 @@
 from activity_browser.ui.wizards import UncertaintyWizard
 from .base import BaseTreeModel, EditablePandasModel, TreeItem
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class BaseParameterModel(EditablePandasModel):
     COLUMNS = []
@@ -232,7 +238,7 @@ def parse_parameter(cls, parameter) -> dict:
             act = bw.get_activity(row["key"])
         except:
             # Can occur if an activity parameter exists for a removed activity.
-            print("Activity {} no longer exists, removing parameter.".format(row["key"]))
+            log.info("Activity {} no longer exists, removing parameter.".format(row["key"]))
             signals.clear_activity_parameter.emit(
                 parameter.database, parameter.code, parameter.group
             )
@@ -354,7 +360,7 @@ def build_exchanges(cls, act_param, parent: TreeItem) -> None:
                 parent.appendChild(item)
             except DoesNotExist as e:
                 # The exchange is coming from a deleted database, remove it
-                print("Broken exchange: {}, removing.".format(e))
+                log.warning("Broken exchange: {}, removing.".format(e))
                 signals.exchanges_deleted.emit([exc])
 
 
diff --git a/activity_browser/ui/tables/views.py b/activity_browser/ui/tables/views.py
index bd8ac6355..fdef08653 100644
--- a/activity_browser/ui/tables/views.py
+++ b/activity_browser/ui/tables/views.py
@@ -14,6 +14,12 @@
 from .delegates import ViewOnlyDelegate
 from .models import PandasModel
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class ABDataFrameView(QTableView):
     """ Base class for showing pandas dataframe objects as tables.
@@ -523,7 +529,7 @@ def set_filters(self, mask) -> None:
         self.activate_filter = True
         self.invalidateFilter()
         self.activate_filter = False
-        print('{} filter matches found'.format(self.matches))
+        log.info('{} filter matches found'.format(self.matches))
 
     def clear_filters(self) -> None:
         self.mask = None
diff --git a/activity_browser/ui/web/base.py b/activity_browser/ui/web/base.py
index 35f3f5479..47aaa78a9 100644
--- a/activity_browser/ui/web/base.py
+++ b/activity_browser/ui/web/base.py
@@ -15,6 +15,12 @@
 from ...ui.icons import qicons
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class BaseNavigatorWidget(QtWidgets.QWidget):
     HELP_TEXT = """
@@ -140,7 +146,7 @@ def node_clicked(self, click_text: str):
         """
         click_dict = json.loads(click_text)
         click_dict["key"] = (click_dict["database"], click_dict["id"])  # since JSON does not know tuples
-        print("Click information: ", click_dict)
+        log.info("Click information: ", click_dict) # TODO click_dict needs correcting
         self.update_graph.emit(click_dict)
 
     @Slot(str, name="download_triggered")
diff --git a/activity_browser/ui/web/navigator.py b/activity_browser/ui/web/navigator.py
index d7bb1fb32..761b45848 100644
--- a/activity_browser/ui/web/navigator.py
+++ b/activity_browser/ui/web/navigator.py
@@ -14,6 +14,12 @@
 from ...signals import signals
 from ...bwutils.commontasks import identify_activity_type
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 # TODO:
 # save graph as image
 # zoom reverse direction between canvas and minimap
@@ -154,12 +160,12 @@ def is_expansion_mode(self) -> bool:
     def toggle_navigation_mode(self):
         mode = next(self.navigation_label)
         self.button_navigation_mode.setText(mode)
-        print("Switched to:", mode)
+        log.info("Switched to:", mode)
         self.checkbox_remove_orphaned_nodes.setVisible(self.is_expansion_mode)
         self.checkbox_direct_only.setVisible(self.is_expansion_mode)
 
     def new_graph(self, key: tuple) -> None:
-        print("New Graph for key: ", key)
+        log.info("New Graph for key: ", key)
         self.graph.new_graph(key)
         self.send_json()
 
@@ -188,15 +194,15 @@ def update_graph(self, click_dict: dict) -> None:
             self.new_graph(key)
         else:
             if keyboard["alt"]:  # delete node
-                print("Deleting node: ", key)
+                log.info("Deleting node: ", key)
                 self.graph.reduce_graph(key)
             else: # expansion mode
-                print("Expanding graph: ", key)
+                log.info("Expanding graph: ", key)
                 if keyboard["shift"]:  # downstream expansion
-                    print("Adding downstream nodes.")
+                    log.info("Adding downstream nodes.")
                     self.graph.expand_graph(key, down=True)
                 else:  # upstream expansion
-                    print("Adding upstream nodes.")
+                    log.info("Adding upstream nodes.")
                     self.graph.expand_graph(key, up=True)
             self.send_json()
 
@@ -332,7 +338,7 @@ def reduce_graph(self, key: tuple) -> None:
         Can lead to orphaned nodes, which can be removed or kept.
         """
         if key == self.central_activity.key:
-            print("Cannot remove central activity.")
+            log.warning("Cannot remove central activity.")
             return
         act = bw.get_activity(key)
         self.nodes.remove(act)
@@ -376,9 +382,9 @@ def format_as_weighted_edges(exchanges, activity_objects=False):
         count = 1
         for count, key in enumerate(orphaned_node_ids, 1):
             act = bw.get_activity(key)
-            print(act["name"], act["location"])
+            log.info(act["name"], act["location"])
             self.nodes.remove(act)
-        print("\nRemoved ORPHANED nodes:", count)
+        log.info("\nRemoved ORPHANED nodes:", count)
 
         # update edges again to remove those that link to nodes that have been deleted
         self.remove_outside_exchanges()
@@ -394,7 +400,7 @@ def get_json_data(self) -> Optional[str]:
             A JSON representation of this.
             """
         if not self.nodes:
-            print("Graph has no nodes (activities).")
+            log.info("Graph has no nodes (activities).")
             return
 
         data = {
diff --git a/activity_browser/ui/web/sankey_navigator.py b/activity_browser/ui/web/sankey_navigator.py
index e85ba57eb..ca5c6f5d3 100644
--- a/activity_browser/ui/web/sankey_navigator.py
+++ b/activity_browser/ui/web/sankey_navigator.py
@@ -14,6 +14,12 @@
 from ...bwutils.superstructure.graph_traversal_with_scenario import GraphTraversalWithScenario
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 # TODO:
 # switch between percent and absolute values
@@ -208,7 +214,7 @@ def update_calculation_setup(self, cs_name=None) -> None:
         self.method_cb.blockSignals(False)
 
     def new_sankey(self) -> None:
-        print("New Sankey for CS: ", self.cs)
+        log.info("New Sankey for CS: ", self.cs)
         demand_index = self.func_unit_cb.currentIndex()
         method_index = self.method_cb.currentIndex()
 
@@ -228,7 +234,7 @@ def update_sankey(self, demand, method, scenario_index: int = None, method_index
                       scenario_lca: bool = False, cut_off=0.05,
                       max_calc=100) -> None:
         """Calculate LCA, do graph traversal, get JSON graph data for this, and send to javascript."""
-        print("Demand / Method: {} {}".format(demand, method))
+        log.info("Demand / Method: {} {}".format(demand, method))
         start = time.time()
 
         try:
@@ -240,7 +246,7 @@ def update_sankey(self, demand, method, scenario_index: int = None, method_index
 
         except ValueError as e:
             QtWidgets.QMessageBox.information(None, "Not possible.", str(e))
-        print("Completed graph traversal ({:.2g} seconds, {} iterations)".format(time.time() - start, data["counter"]))
+        log.info("Completed graph traversal ({:.2g} seconds, {} iterations)".format(time.time() - start, data["counter"]))
 
         self.graph.new_graph(data)
         self.has_sankey = bool(self.graph.json_data)
diff --git a/activity_browser/ui/web/webutils.py b/activity_browser/ui/web/webutils.py
index 53a38c197..1b4bd7a56 100644
--- a/activity_browser/ui/web/webutils.py
+++ b/activity_browser/ui/web/webutils.py
@@ -4,7 +4,6 @@
 
 # type "localhost:3999" in Chrome for DevTools of AB web content
 from activity_browser.utils import get_base_path
-
 os.environ['QTWEBENGINE_REMOTE_DEBUGGING'] = '3999'
 
 
diff --git a/activity_browser/ui/widgets/biosphere_update.py b/activity_browser/ui/widgets/biosphere_update.py
index 118e07caa..a7541c417 100644
--- a/activity_browser/ui/widgets/biosphere_update.py
+++ b/activity_browser/ui/widgets/biosphere_update.py
@@ -6,6 +6,12 @@
 import bw2io.data as data
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+
 
 class BiosphereUpdater(QtWidgets.QProgressDialog):
     def __init__(self, parent=None):
@@ -48,5 +54,5 @@ def run(self):
                 update_bio = getattr(data, patch)
                 update_bio()
         except ValidityError as e:
-            print("Could not patch biosphere: {}".format(str(e)))
+            log.error("Could not patch biosphere: {}".format(str(e)))
             self.exit(1)
diff --git a/activity_browser/ui/wizards/db_import_wizard.py b/activity_browser/ui/wizards/db_import_wizard.py
index 30f579db4..a94eddab2 100644
--- a/activity_browser/ui/wizards/db_import_wizard.py
+++ b/activity_browser/ui/wizards/db_import_wizard.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 import io
 from pathlib import Path
-from pprint import pprint
 import subprocess
 import tempfile
 import zipfile
@@ -23,6 +22,12 @@
 from ..style import style_group_box
 from ..widgets import DatabaseLinkingDialog
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger)
+
 # TODO: Rework the entire import wizard, the amount of different classes
 #  and interwoven connections makes the entire thing nearly incomprehensible.
 
@@ -108,7 +113,7 @@ def closeEvent(self, event):
         event.accept()
 
     def cancel_thread(self):
-        print('\nDatabase import interrupted!')
+        log.info('\nDatabase import interrupted!')
         import_signals.cancel_sentinel = True
         self.cleanup()
 
@@ -824,7 +829,7 @@ def run_local_import(self):
                 # With the changes to the ABExcelImporter and ABPackage classes
                 # this should not really trigger for data exported from AB.
                 if db.name != self.db_name:
-                    print("WARNING: renaming database '{}' to '{}', parameters lost.".format(
+                    log.warning("renaming database '{}' to '{}', parameters lost.".format(
                         db.name, self.db_name))
                     db.rename(self.db_name)
                 import_signals.db_progress.emit(1, 1)
@@ -850,7 +855,7 @@ def run_local_import(self):
             )
         except StrategyError as e:
             # Excel import failed because extra databases were found, relink
-#            print("Could not link exchanges, here are 10 examples.:") # THREAD UNSAFE FUNCTIONS
+            log.error("Could not link exchanges, here are 10 examples.:") # THREAD UNSAFE FUNCTIONS
 #            pprint(e.args[0])
             self.delete_canceled_db()
             import_signals.links_required.emit(e.args[0], e.args[1])
@@ -871,7 +876,7 @@ def run_local_import(self):
     def delete_canceled_db(self):
         if self.db_name in bw.databases:
             del bw.databases[self.db_name]
-            print(f'Database {self.db_name} deleted!')
+            log.info(f'Database {self.db_name} deleted!')
 
 
 class EcoinventLoginPage(QtWidgets.QWizardPage):
@@ -1151,7 +1156,7 @@ def extract(cls, dirpath: str, db_name: str, *args, **kwargs):
         dir_path = str(dir_path)
         for i, filename in enumerate(file_list, start=1):
             if import_signals.cancel_sentinel:
-                print(f'Extraction canceled at position {i}!')
+                log.info(f'Extraction canceled at position {i}!')
                 raise ImportCanceledError
 
             data.append(cls.extract_activity(dir_path, filename, db_name))
@@ -1172,7 +1177,7 @@ def _efficient_write_many_data(self, *args, **kwargs):
     def _efficient_write_dataset(self, *args, **kwargs):
         index = args[0]
         if import_signals.cancel_sentinel:
-            print(f'\nWriting canceled at position {index}!')
+            log.info(f'\nWriting canceled at position {index}!')
             raise ImportCanceledError
         import_signals.db_progress.emit(index+1, self.total)
         return super()._efficient_write_dataset(*args, **kwargs)
diff --git a/activity_browser/ui/wizards/settings_wizard.py b/activity_browser/ui/wizards/settings_wizard.py
index db3f56e7a..04cd7aa4f 100644
--- a/activity_browser/ui/wizards/settings_wizard.py
+++ b/activity_browser/ui/wizards/settings_wizard.py
@@ -8,6 +8,12 @@
 from ...settings import ab_settings
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger)
+
 
 class SettingsWizard(QtWidgets.QWizard):
     def __init__(self, parent=None):
@@ -30,7 +36,7 @@ def save_settings(self):
         if field and field != current_bw_dir:
             ab_settings.custom_bw_dir = field
             ab_settings.current_bw_dir = field
-            print("Saved startup brightway directory as: ", field)
+            log.info("Saved startup brightway directory as: ", field)
 
         # project
         field_project = self.field("startup_project")
@@ -38,13 +44,13 @@ def save_settings(self):
         if field_project and field_project != current_startup_project:
             new_startup_project = field_project
             ab_settings.startup_project = new_startup_project
-            print("Saved startup project as: ", new_startup_project)
+            log.info("Saved startup project as: ", new_startup_project)
 
         ab_settings.write_settings()
         signals.switch_bw2_dir_path.emit(field)
 
     def cancel(self):
-        print("Going back to before settings were changed.")
+        log.info("Going back to before settings were changed.")
         if bw.projects._base_data_dir != self.last_bwdir:
             signals.switch_bw2_dir_path.emit(self.last_bwdir)
             signals.change_project.emit(self.last_project)  # project changes only if directory is changed
@@ -220,7 +226,7 @@ def update_project_combo(self, initialization: bool = True, path: str = None):
         if self.project_names:
             self.startup_project_combobox.addItems(self.project_names)
         else:
-            print("Warning: No projects found in this directory.")
+            log.warning("No projects found in this directory.")
 #            return
         if ab_settings.startup_project in self.project_names:
             self.startup_project_combobox.setCurrentText(ab_settings.startup_project)
diff --git a/activity_browser/ui/wizards/uncertainty.py b/activity_browser/ui/wizards/uncertainty.py
index 038068b77..4c27550d7 100644
--- a/activity_browser/ui/wizards/uncertainty.py
+++ b/activity_browser/ui/wizards/uncertainty.py
@@ -11,6 +11,12 @@
 from ...bwutils.uncertainty import EMPTY_UNCERTAINTY
 from ...signals import signals
 
+import logging
+from activity_browser.logger import ABHandler
+
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger)
+
 
 class UncertaintyWizard(QtWidgets.QWizard):
     """Using this wizard, guide the user through selecting an 'uncertainty'
@@ -573,7 +579,7 @@ def initializePage(self):
             matrix = PedigreeMatrix.from_dict(obj.uncertainty.get("pedigree", {}))
             self.pedigree = matrix.factors
         except AssertionError as e:
-            print("Could not extract pedigree data: {}".format(str(e)))
+            log.info("Could not extract pedigree data: {}".format(str(e)))
             self.pedigree = {}
         self.check_complete()
 
diff --git a/pytest.ini b/pytest.ini
index e43dc27cb..c13c3f06a 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,3 +1,4 @@
 [pytest]
 testpaths=tests
 qt_api=pyside2
+log_cli=true
diff --git a/run-activity-browser.py b/run-activity-browser.py
index de81f5c4b..5a07f126e 100644
--- a/run-activity-browser.py
+++ b/run-activity-browser.py
@@ -1,5 +1,13 @@
 # -*- coding: utf-8 -*-
+import logging
+
+from activity_browser.logger import ABHandler
+
 from activity_browser import run_activity_browser
 
 
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, __name__)
+log.info("The Activity-Browser log file can be found at {}".format(log.log_file_path()))
+
 run_activity_browser()
\ No newline at end of file
diff --git a/tests/pytest.ini b/tests/pytest.ini
new file mode 100644
index 000000000..7c658ea19
--- /dev/null
+++ b/tests/pytest.ini
@@ -0,0 +1,4 @@
+[pytest]
+testpaths=tests
+qt_api=pyside2
+log_level=INFO
diff --git a/tests/test_uncertainty_wizard.py b/tests/test_uncertainty_wizard.py
index 1797a5191..6d5ba710c 100644
--- a/tests/test_uncertainty_wizard.py
+++ b/tests/test_uncertainty_wizard.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
+import logging
 import sys
 
+
 from bw2data.parameters import ProjectParameter
 import numpy as np
 from PySide2.QtWidgets import QMessageBox, QWizard
@@ -13,10 +15,18 @@
 from activity_browser.ui.wizards import UncertaintyWizard
 from activity_browser.signals import signals
 
+from activity_browser.logger import ABHandler
+
 """
 Mess around with the uncertainty wizard.
 """
 
+logger = logging.getLogger('ab_logs')
+log = ABHandler.setup_with_logger(logger, "uncertainty_wizard_test")
+
+log.setLevel(logging.INFO, True)
+log.propagate = True
+
 @pytest.mark.skipif(sys.platform=='darwin', reason="tests segfaults on osx")
 def test_wizard_fail(qtbot):
     """Can't create a wizard if no uncertainty interface exists."""
@@ -26,8 +36,9 @@ def test_wizard_fail(qtbot):
 
 
 @pytest.mark.skipif(sys.platform=='darwin', reason="tests segfaults on osx")
-def test_uncertainty_wizard_simple(qtbot, bw2test, capsys):
+def test_uncertainty_wizard_simple(qtbot, bw2test, caplog):
     """Use extremely simple text to open the wizard and go to all the pages."""
+    caplog.set_level(logging.INFO)
     param = ProjectParameter.create(name="test1", amount=3)
     wizard = UncertaintyWizard(param, None)
     qtbot.addWidget(wizard)
@@ -42,8 +53,8 @@ def test_uncertainty_wizard_simple(qtbot, bw2test, capsys):
         wizard.type.pedigree.click()
 
     # Pedigree is empty, so complaint is issued.
-    captured = capsys.readouterr()
-    assert "Could not extract pedigree data" in captured.out
+    captured = caplog.text
+    assert "Could not extract pedigree data" in captured
 
     # Now go back for giggles.
     with qtbot.waitSignal(wizard.currentIdChanged, timeout=100):