Try this
HDD reset and then a forced software download.
Start by turning the power off at the wall, switch back on and then hold the left and right buttons (either side of select) on the front of the box and hold firmly for around a minute. The circle at the front of the box will illuminate, release the two buttons and press the select button. The light will now rotate anti clockwise, once this has finished turn the power off again and hold the backup button, turn the power back on and wait for all lights on the fron t of the box to illuminate. "Updating System Software" will be displayed on the screen.
WARNING this will erase everything on the HDD!
Hope this helps
i tried this on mines when my hdd showed it had 54% left when there was nothing in the planner and now it`s a full 100% and i got this info on here after searching for a while hope this helps
Gambo, January 2011