My Sky Plus box has stopped recording even though the memory is empty. When record is selected in appears in the list, but as the program start "failed" appears

Gary Knibbs, August 2009

You could do forced format which can remedy alot of hard drive recording faults hold the left and right arrow keys when green circle comes on press select and wait untill reformats drive.
Otherwise send it to Digi Repairs UK as I think there the only people apart from Sky who know hoe to repair Sky+

John Barnes, October 2009

Have you canceled your Sky Subscription because you need one in order for the record function to work.

Even if you haven't, I'd start by giving Sky a call.

T, August 2009