diff --git a/efb_wechat_slave/__init__.py b/efb_wechat_slave/__init__.py
index 45e1c17..7d65499 100644
--- a/efb_wechat_slave/__init__.py
+++ b/efb_wechat_slave/__init__.py
@@ -257,6 +257,9 @@ def master_qr_code(self, uuid, status, qrcode=None):
             coordinator.send_message(msg)
 
     def exit_callback(self):
+        # Don't send prompt if there's nowhere to send.
+        if not coordinator.master:
+            return
         self.logger.debug('Calling exit callback...')
         if self._stop_polling_event.is_set():
             return