--- a/src/polkit/polkitsystembusname.c
+++ b/src/polkit/polkitsystembusname.c
@@ -435,6 +435,9 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName           *system_bus
   while (!((data.retrieved_uid && data.retrieved_pid) || data.caught_error))
     g_main_context_iteration (tmp_context, TRUE);
 
+  if (data.caught_error)
+    goto out;
+
   if (out_uid)
     *out_uid = data.uid;
   if (out_pid)