Perspective shifting indie puzzler/platformer, Fez, is a game I personally enjoyed immensely. However, shortly after its release, some users began reporting some pretty problematic issues, most prominently, an infinite death loop. A patch has finally been released with the purpose of eliminating such issues, but according to Polytron, the patch has some pretty significant issues of its own. Foremost among these issues is that “the save file can be seen as corrupted by the game after installing the patch.” Ouch.
The devs suggest clearing the Xbox’s system cache, as it “should resolve the issue.” But if that doesn’t work, you’re, well, shit out of luck, to use the technical term – aside from clearing the system cache, “there is no known workaround.” So, yeah, just decline the update if you boot up the game. You’ll be disconnected from Xbox Live while you play, but that seems preferable to losing all save data if you ask me.