We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
A friend of mine had a similar problem, Attachments would save for weapons and vehicles. If I remember he deleted the Multi-player Update from is HDD (just the update, nothing else) Cleared his System Cach and redownload the Update. His game then ran as
it should. As long as you only delete the update there's no harm in trying this. Hope it helps.