diff --git a/app/js/messages_manager.js b/app/js/messages_manager.js
index 4433a1cd..5d1c2954 100644
--- a/app/js/messages_manager.js
+++ b/app/js/messages_manager.js
@@ -1691,7 +1691,7 @@ angular.module('myApp.services')
   }
 
   function wrapForDialog (msgID, dialog) {
-    var useCache = dialog !== undefined;
+    var useCache = msgID && dialog !== undefined;
     var unreadCount = dialog && dialog.unread_count;
 
     if (useCache && messagesForDialogs[msgID] !== undefined) {