The latest patch for Aliens: Colonial Marines is out now, but Xbox 360 owners might want to avoid it, as reports indicate that installing the update will result in losing all your progress in the game. The bug is allegedly caused by the fact that Gearbox decided to store the save-date in the Xbox’s cache, which the latest update cheekily clears.
The Gearbox forum is currently receiving a flood of topics where people complaint about having lost all their saves, and a user by the name of “shadyshall” has started an official thread for people to share their stories and theories on. Gearbox has yet to release an official statement regarding the bug.
According to a post on xbox360achievements.org, the same problem is tormenting Borderlands 2. If you care for your save-files, then you may want to keep your Xbox offline, until a fix has been released.
[Source]