diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index cea3d5c951..08f63be96c 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -991,7 +991,7 @@ def decrypt_sig(mobj):
                         existing_format.update(f)
 
             except (ExtractorError, KeyError) as e:
-                self.report_warning('Skipping DASH manifest: %s' % e, video_id)
+                self.report_warning('Skipping DASH manifest: %r' % e, video_id)
 
         self._sort_formats(formats)