diff --git a/rhodecode/lib/vcs/exceptions.py b/rhodecode/lib/vcs/exceptions.py
--- a/rhodecode/lib/vcs/exceptions.py
+++ b/rhodecode/lib/vcs/exceptions.py
@@ -220,7 +220,7 @@ def map_vcs_exceptions(func):
                 if any(e.args):
                     _args = [a for a in e.args]
                     # replace the first argument with a prefix exc name
-                    args = ['{}:'.format(exc_name, _args[0] if _args else '?')] + _args[1:]
+                    args = ['{}:{}'.format(exc_name, _args[0] if _args else '?')] + _args[1:]
                 else:
                     args = [__traceback_info__ or '{}: UnhandledException'.format(exc_name)]
                 if debug or __traceback_info__ and kind not in ['unhandled', 'lookup']: