I can do everything else in reach but when ever I try to play on the map "Corvette" My Xbox says to clean the disk but I don't understand because My game is installed to my HDD... I've tried reinstalling it and cleaning the disk. I've even tried to play without my HDD attached to my console, still nothing. It's not too bothersome just inconvenient. I believe it is only the map "Corvette" but it might be my Xbox since It has a bunch of ether problems that I just suffer through (like constant freezing and crashing) because I can't afford to get them fixed. I very much like to know why it does this even though I have the game installed.