diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -540,7 +540,7 @@
         except ValueError as e:
             # Can be raised on Python 3.8 when path is invalid.
             raise error.Abort(
-                _(b'invalid path %s: %s') % (path, pycompat.bytestr(e))
+                _(b'invalid path %s: %s') % (path, stringutil.forcebytestr(e))
             )
 
         raise error.RepoError(_(b'repository %s not found') % path)