So, about 50 hours into the game, all my saved games are no longer working. Either they lock up while trying to load, or I get an error message saying: "This save game relies on downloadable content that is no longer available. Some objects may be no longer available. Continue loading?". Hitting either Yes or No will give another error saying the storage device is no longer available and it will drop me back to the Fallout New Vegas main menu. I've tried deleting the xbox cache, deleting and reinstalling the Tribal Pack DLC and recovering GamerTag to no avail. I'm pretty disappointed that I spent so much time playing this game, only to wind up with all my games getting corrupted.

join the club.

Hah.. I guess so. I had luckily been dodging a lot of issues people have complained about, until this. Now, I'm upset. Did Bethesda not even bother to QA this game? Is there any warranty on the purchase? Or by cracking open the case did I agree to some EULA that said "TOO BAD IF IT BREAKS!"

This seems to be one of the biggest issues xbox users are having. Typically it happens because you finished "Come fly with Me" quest after talking to Manny in Novac. If you load a save prior to finishing that quest you should be fine. There is no error while you are playing, you have to actually leave the game to get the error when you try to play next. If you did the quest then played another 20hrs without exiting the game you lost 20hrs of time. The "Come fly with me" quest is given by Manny to tell you the next step in the main quest, but you can just access his terminal in Novac to get the same info and progress in the main quest. You are not alone in your pain, many of us have had the same thing happen.