i have the same problem after i updated my dashboard,my xbox says that the updates are corrupted...... + do you have this problem with other/new title updates? + tray cleaning your console's cache......
I just try Assassin's Creed 3, and it was perfect! only COD: Black Ops II, everything is clean .. excludes HD game to see if improvement ... still the same problem!
http://www.xbuc.net/?details=COD%20Black%20Ops%20II ID : 05C7492A Region Free!! if anyone can, please tell!