Q: I lost my Achievement progress and or MP Level– For some reason; I’ve lost any progress I made toward achievements/rank. What happened?

A: I’ve seen people reporting this problem. (Even after TU4) A couple of notes for everyone playing Gears of War 2:

Please do not shut down your console or launch the Dash in the middle of a game. Quit to the main menu. All save data is stored in the profile, and quitting prematurely can corrupt the Gears 2 data in the profile and therefore effectively reset it. There are several times that a game saves a significant amount of data. This happens after you cancel matchmaking (”Updating: Network settings are being updated”) and when you hit a checkpoint in the campaign “Saving: Please do not shut down your console”). But there are also several quick saves that happen in SP and MP, such as when you pick up a collectable or earn progress towards an achievement. Quitting out or shutting off the console prematurely is bad. The safest way to exit Gears of War is to quit to the main menu first. Also try to avoid playing offline because that seems to affect the rank as well. Do not take your profile to play on someone else’s Xbox that’s does not have TU3 or later.

Originally Posted by Rod Fergusson on Gears of War official forums

Here’s what we know

 MP level gets reset.

This is an issue where after you have upgraded to TU3 on one box, you play on another box that has not yet been upgraded and so it throws out all the new TU3 data in your profile. This one is not really fixable because it would require us going back in time and making the released version aware of the new data and not throw it away. Since we track matches played, we’re investigating ways of restoring player levels in a future title update, even if it’s not 100%, it should be better than nothing. We’re really sorry for this issue but at the time of release we had no idea we were going to change the profile data so fundamentally in future title updates.