diff --git a/core/modules/upgraders/system.js b/core/modules/upgraders/system.js
index a93a57712..a653a75b1 100644
--- a/core/modules/upgraders/system.js
+++ b/core/modules/upgraders/system.js
@@ -12,7 +12,7 @@ Upgrader module that suppresses certain system tiddlers that shouldn't be import
 /*global $tw: false */
 "use strict";
 
-var DONT_IMPORT_LIST = ["$:/Import"],
+var DONT_IMPORT_LIST = ["$:/Import", "$:/build"],
 	UNSELECT_PREFIX_LIST = ["$:/temp/","$:/state/","$:/StoryList","$:/HistoryList"],
 	WARN_IMPORT_PREFIX_LIST = ["$:/core/modules/"];