diff --git a/chrome/content/zotero/xpcom/sync/syncRunner.js b/chrome/content/zotero/xpcom/sync/syncRunner.js
index c99fa8f35..8c63e7075 100644
--- a/chrome/content/zotero/xpcom/sync/syncRunner.js
+++ b/chrome/content/zotero/xpcom/sync/syncRunner.js
@@ -223,7 +223,7 @@ Zotero.Sync.Runner_Module = function (options = {}) {
 			}
 			
 			Zotero.debug("Done syncing");
-			Zotero.Notifier.trigger('finish', 'sync', librariesToSync);
+			Zotero.Notifier.trigger('finish', 'sync', librariesToSync || []);
 		}
 	});