diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index a5c5be1666..ce49ddbad2 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -972,7 +972,7 @@ def shutdown(self, write_settings=True):
         if write_settings:
             self.write_settings()
         self.check_messages_timer.stop()
-        if hasattr(self, 'update_checker'):
+        if getattr(self, 'update_checker', None):
             self.update_checker.shutdown()
         self.listener.close()
         self.job_manager.server.close()