diff --git a/moto/cloudformation/exceptions.py b/moto/cloudformation/exceptions.py
index 4bbbbbcf..ed285682 100644
--- a/moto/cloudformation/exceptions.py
+++ b/moto/cloudformation/exceptions.py
@@ -11,7 +11,7 @@ class UnformattedGetAttTemplateException(Exception):
 class ValidationError(BadRequest):
     def __init__(self, name_or_id, message=None):
         if message is None:
-            message="Stack:{0} does not exist".format(name_or_id),
+            message="Stack with id {0} does not exist".format(name_or_id)
 
         template = Template(ERROR_RESPONSE)
         super(ValidationError, self).__init__()