diff --git a/src/fmu/dataio/_metadata.py b/src/fmu/dataio/_metadata.py
index 39857ca84..709f4b3c4 100644
--- a/src/fmu/dataio/_metadata.py
+++ b/src/fmu/dataio/_metadata.py
@@ -12,6 +12,7 @@
 from dataclasses import dataclass, field
 from datetime import timezone
 from pathlib import Path
+from tempfile import NamedTemporaryFile
 from typing import Any, Final
 from warnings import warn
 
@@ -305,15 +306,14 @@ def _populate_meta_file(self) -> None:
             self.meta_file["absolute_path_symlink"] = fdata.absolute_path_symlink
 
         if self.compute_md5:
-            logger.info("Compute MD5 sum for tmp file...")
-            _, self.meta_file["checksum_md5"] = export_file_compute_checksum_md5(
-                self.obj,
-                "tmp",  # type: ignore
-                # tmp = true given, this arg is not needed.
-                self.objdata.extension,
-                tmp=True,
-                flag=self.dataio._usefmtflag,
-            )
+            with NamedTemporaryFile(buffering=0) as tf:
+                logger.info("Compute MD5 sum for tmp file...: %s", tf.name)
+                self.meta_file["checksum_md5"] = export_file_compute_checksum_md5(
+                    self.obj,
+                    Path(tf.name),
+                    self.objdata.extension,
+                    flag=self.dataio._usefmtflag,
+                )
         else:
             logger.info("Do not compute MD5 sum at this stage!")
             self.meta_file["checksum_md5"] = None
diff --git a/src/fmu/dataio/_utils.py b/src/fmu/dataio/_utils.py
index 883147c7c..81fdd4642 100644
--- a/src/fmu/dataio/_utils.py
+++ b/src/fmu/dataio/_utils.py
@@ -7,7 +7,6 @@
 import logging
 import os
 import shutil
-import tempfile
 import uuid
 import warnings
 from copy import deepcopy
@@ -174,22 +173,10 @@ def export_file_compute_checksum_md5(
     filename: Path,
     extension: str,
     flag: str | None = None,
-    tmp: bool = False,
-) -> tuple[Path | None, str]:
-    """Export and compute checksum, with possibility to use a tmp file."""
-
-    usefile: Path | None = filename
-    if tmp:
-        tmpdir = tempfile.TemporaryDirectory()
-        usefile = Path(tmpdir.name) / "tmpfile"
-
-    assert usefile is not None
-    export_file(obj, usefile, extension, flag=flag)
-    checksum = md5sum(usefile)
-    if tmp:
-        tmpdir.cleanup()
-        usefile = None
-    return usefile, checksum
+) -> str:
+    """Export and compute checksum"""
+    export_file(obj, filename, extension, flag=flag)
+    return md5sum(filename)
 
 
 def create_symlink(source: str, target: str) -> None:
diff --git a/src/fmu/dataio/dataio.py b/src/fmu/dataio/dataio.py
index 00f19d2af..55b323968 100644
--- a/src/fmu/dataio/dataio.py
+++ b/src/fmu/dataio/dataio.py
@@ -906,17 +906,14 @@ def export(
 
         obj = self._check_obj_if_file(obj)
         logger.info("Export to file and compute MD5 sum, using flag: <%s>", useflag)
-        toutfile, md5 = export_file_compute_checksum_md5(
+        # inject md5 checksum in metadata
+        metadata["file"]["checksum_md5"] = export_file_compute_checksum_md5(
             obj,
             outfile,
             outfile.suffix,
             flag=useflag,  # type: ignore
             # BUG(?): Looks buggy, if flag is bool export_file will blow up.
         )
-        assert toutfile is not None
-        outfile = toutfile
-        # inject md5 checksum in metadata
-        metadata["file"]["checksum_md5"] = md5
         logger.info("Actual file is:   %s", outfile)
 
         if self._config_is_valid:
@@ -1511,12 +1508,10 @@ def export(self, obj: object, **kwargs: object) -> str:
         metafile = outfile.parent / ("." + str(outfile.name) + ".yml")
 
         logger.info("Export to file and compute MD5 sum")
-        toutfile, md5 = export_file_compute_checksum_md5(obj, outfile, outfile.suffix)
-        assert toutfile is not None
-        outfile = Path(toutfile)
-
         # inject the computed md5 checksum in metadata
-        metadata["file"]["checksum_md5"] = md5
+        metadata["file"]["checksum_md5"] = export_file_compute_checksum_md5(
+            obj, outfile, outfile.suffix
+        )
 
         export_metadata_file(metafile, metadata, savefmt=self.meta_format)
         logger.info("Actual file is:   %s", outfile)