It very well could be that your hard drive has a setting that if the drive isnt being touched for an amount of time, it will automatically shut off or go on standby causeing your game to freeze. There have been members that have had the problem of it shutting down after some time of not being used. The thing with loading a game using HDD is that eventhough you are playing the game, the HDD isnt actually being used all the time. It will be used to load parts of the game if not the entire game but thats all. So if you have a drive that will go on standby after time not being used, you would have to change that setting. You would have to read your manual.