--- a/addon-sdk/source/lib/sdk/l10n/properties/core.js
+++ b/addon-sdk/source/lib/sdk/l10n/properties/core.js
@@ -8,16 +8,20 @@ const { newURI } = require('../../url/ut
 const { getRulesForLocale } = require("../plural-rules");
 const { getPreferedLocales } = require('../locale');
 const { rootURI } = require("@loader/options");
 const { Services } = Cu.import("resource://gre/modules/Services.jsm", {});
 
 const baseURI = rootURI + "locale/";
 const preferedLocales = getPreferedLocales(true);
 
+// Make sure we don't get stale data after an update
+// (See Bug 1300735 for rationale).
+Services.strings.flushBundles();
+
 function getLocaleURL(locale) {
   // if the locale is a valid chrome URI, return it
   try {
     let uri = newURI(locale);
     if (uri.scheme == 'chrome')
       return uri.spec;
   }
   catch(_) {}