I am surprised that this problem hasn't been seen by more players. The first time this happened to me I lost all of my Multiplayer data. I read on the Internet where a few people had reported this problem, but there was so few reports that I didn't think it was likely to happen to me. I was very wrong about that. After it happened the first time I started backing up the Profile Data file every time I obtained an emblem. It is a good thing I did this. Two days later the Profile Data file was corrupted again, but this time I restored the file with the backup file and none of my emblems or statistics were lost.

The second time the file was corrupted it appeared grayed out when I went into the Rage saves folder, which is where the Rage Profile Data is stored. This did not happen the first time the file was corrupted. If you care about keeping your earned Multiplayer emblems and statistics, you should backup the Rage Profile Data every time you make any significant progress in the game.