diff --git a/mercurial/wireproto.py b/mercurial/wireproto.py
--- a/mercurial/wireproto.py
+++ b/mercurial/wireproto.py
@@ -229,7 +229,7 @@ def unbundle(repo, proto, heads):
 
     # fail early if possible
     if not check_heads():
-        return _('unsynced changes')
+        return 'unsynced changes'
 
     # write bundle data to temporary file because it can be big
     fd, tempname = tempfile.mkstemp(prefix='hg-unbundle-')
@@ -243,7 +243,7 @@ def unbundle(repo, proto, heads):
             if not check_heads():
                 # someone else committed/pushed/unbundled while we
                 # were transferring data
-                return _('unsynced changes')
+                return 'unsynced changes'
 
             # push can proceed
             fp.seek(0)