E68

You need a new hard drive or reformat the one you have with a laptop or PC.
Controll Panel > Administrative Tools > Computer Management > Disk Management (on left)

Hook up the hard drive with an external USB case ($5 on eBay). Right click on left side and initialize.
When that is finished, right click in the middle of that hard disk (where it says --GB unallocated) and click on format. You need to for mat with NTFS first then follow the steps again to format it in FAT. When thats done, re-install the hard drive into the case and reattach to the Xbox and it should be good to go!! Good luck and happy gaming!!!

I must be a frickin genius cuz no one else has found this out yet and im not suprised.
this is not a 1 time only thing here, and ull hav 2 do this every time u wanna play, but it works.
its as simple as this: put it in ur freezer. making the hard drive cold compresses the wires into a smaller path, allowing data to flow faster. keep the hard drive in the freezer for about 15 minutes to a half an hour. hope this works