Microsoft XBox 360 Manual page 18

Hard Drive or USB Flash Drive Not
Listed as a Storage Device
are sold separately from this version of the
Xbox 360 video game system. If your hard
storage device, try the following, starting
into the hard drive slot and the cover has
been replaced. Turn the console off, then
on again.
on and then off again. Reinsert the hard
drive cover, and turn the console on
again.
another console, or try another storage
device on your console to pinpoint the
problem.
16
NOTE
Damaged storage devices might not show
up in the Xbox Guide and could harm your
Xbox 360 console. Storage devices that have
been crushed, immersed in liquids, exposed
to magnets, or exposed to intense heat may
be damaged beyond use and will not appear
in your list of storage devices.
USB storage devices must have a capacity of
with Xbox 360. Some slower devices won't
work with Xbox 360.