Hey guys, thank you all for posting in this thread. I want to let you know that we're aware of an issue with achievements, and that we're doing everything we can to resolve it ASAP. At this time, we believe the issue should be resolved. If you're missing achievements, please try signing out of Xbox LIVE, then sign back in. If this doesn't resolve your issue, then you will need to re-download your profile. Please note that this will remove any achievements you might have earned since the issue began, however, they can be re-earned.