diff --git a/browser/base/content/browser-syncui.js b/browser/base/content/browser-syncui.js
index e150a944f1a4..3054abc2dbc5 100644
--- a/browser/base/content/browser-syncui.js
+++ b/browser/base/content/browser-syncui.js
@@ -304,7 +304,7 @@ let gSyncUI = {
   _updateLastSyncItem: function SUI__updateLastSyncItem() {
     let lastSync;
     try {
-      Services.prefs.getCharPref("services.sync.lastSync");
+      lastSync = Services.prefs.getCharPref("services.sync.lastSync");
     }
     catch (e) { };
     if (!lastSync)