diff --git a/hgext/convert/git.py b/hgext/convert/git.py
--- a/hgext/convert/git.py
+++ b/hgext/convert/git.py
@@ -231,7 +231,7 @@ class convert_git(converter_source):
         # Build complete list of tags, both annotated and bare ones
         for line in fh:
             line = line.strip()
-            if line.startswith("error:"):
+            if line.startswith("error:") or line.startswith("fatal:"):
                 raise util.Abort(_('cannot read tags from %s') % self.path)
             node, tag = line.split(None, 1)
             if not tag.startswith(prefix):