Instructions
Plug your storage device into your Xbox 360. Use the console's USB ports to connect the device via the included cable. This can be an external hard drive or a USB flash drive.
Turn on your Xbox 360.
Select "My Xbox" from the console's menu.
Select "System Settings," followed by "Memory."
Choose "All Devices" from the menu to view a list of all memory devices connected to your console. Your flash drive or external hard drive will be among this list.
Select the icon for your storage device. Open the "Gamer Profiles" folder and select your gamertag.
Select the "Move" option. Select "Hard Drive" to transfer the uncorrupted version of your gamertag to your Xbox 360 hard drive.