Well it happened to me last week
Playing Rainbow Six, 360 crashed
forced reboot and no picture came up.... reboot again and this time it sat there saying 1 profile... strange i thought it hasnt logged me in. and i have 2 profiles, mine and the ex's.
looked at profiles and mine wasnt there.....
looked in memory manager and it said, 1 corrupt profile....
deleted the corrupt profile keeping all save and other data other than the profile...
did a gamertag recovery from microsoft (basicaly gets your login and gamer points back)
afer 6 attempts (kept on dropping connection half way through

) i got my gamer tag back.....
WITH NO SAVE DATA!!!!
that means TDU from stcratch!!!!!

Hence i havent been on much this weekend.
thats over 60 hours of TDU play lost. I stil have the achievements so all i have to do is the side missions and 5000miles and then im done but still its a pain in the arse, and ive lost all my cars and cash!!! and as far as TDU is concerned i will ahve to do it all again to get Ace status as its the save that keeps that status but my achievemnts will show that i have completed the game....
few

over......
just hope you never have this happen.