diff --git a/rhodecode/lib/vcs/backends/hg/repository.py b/rhodecode/lib/vcs/backends/hg/repository.py
--- a/rhodecode/lib/vcs/backends/hg/repository.py
+++ b/rhodecode/lib/vcs/backends/hg/repository.py
@@ -83,7 +83,7 @@ class MercurialRepository(BaseRepository
         # NOTE(marcink): since python3 hgsubversion is deprecated.
         # From old installations we might still have this set enabled
         # we explicitly remove this now here to make sure it wont propagate further
-        if config.get('extensions', 'hgsubversion') is not None:
+        if config and config.get('extensions', 'hgsubversion') is not None:
             config.drop_option('extensions', 'hgsubversion')
 
         self.with_wire = with_wire or {"cache": False}  # default should not use cache