diff --git a/yt_dlp/postprocessor/embedthumbnail.py b/yt_dlp/postprocessor/embedthumbnail.py
index cfa51437d..fb778e233 100644
--- a/yt_dlp/postprocessor/embedthumbnail.py
+++ b/yt_dlp/postprocessor/embedthumbnail.py
@@ -105,7 +105,7 @@ def run(self, info):
                     audio.save()
                     temp_filename = filename  # Mutagen saves to the original file
                 except Exception as err:
-                    self.report_warning('unable to embed using mutagen; %s' % error_to_compat_str(err))
+                    self.report_warning(f'unable to embed using mutagen; {err}')
                     success = False
             # Method 2: Use ffmpeg
             else: