diff --git a/seahub/api2/endpoints/query_zip_progress.py b/seahub/api2/endpoints/query_zip_progress.py
index 06b7b48f32..0a7205dcad 100644
--- a/seahub/api2/endpoints/query_zip_progress.py
+++ b/seahub/api2/endpoints/query_zip_progress.py
@@ -13,6 +13,7 @@ from seaserv import seafile_api
 
 logger = logging.getLogger(__name__)
 
+
 class QueryZipProgressView(APIView):
 
     throttle_classes = (UserRateThrottle, )
@@ -35,4 +36,8 @@ class QueryZipProgressView(APIView):
             error_msg = 'Internal Server Error'
             return api_error(status.HTTP_500_INTERNAL_SERVER_ERROR, error_msg)
 
+        if not progress:
+            error_msg = 'progress not found.'
+            return api_error(status.HTTP_404_NOT_FOUND, error_msg)
+
         return Response(json.loads(progress))