diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6784944..523d61a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 Compatibility: requires minimum Kimai 2.5.0
 
 - Added: new created users during import require to change password
+- Changed: Improved error message upon wrong mimetype
 
 ## Version 2.7.0
 
diff --git a/Importer/ImporterService.php b/Importer/ImporterService.php
index d3be8c1..2824f29 100644
--- a/Importer/ImporterService.php
+++ b/Importer/ImporterService.php
@@ -79,7 +79,7 @@ public function import(ImportModel $model, string $importer): ImportData
         }
 
         throw new ImportException(
-            sprintf('Unsupported file given, invalid mimetype (%s). Try to use another browser.', $mimetype)
+            sprintf('Unsupported file given, invalid mimetype (%s / %s). Try to use another browser.', $mimetype, $userMimetype)
         );
     }