In my case itunes froze when my ipod classic was connected and could not be shut down either from the programme or via task manager - I had to power off the pc. I eventually solved it by doing a FULL (not a quick) format of the ipod, then restoring it. After this I sync'd everything again and it now appears OK. Not a quick fix but the only one I know. As to the cause, my only clue is it happened after I sync'd one playlist, rather than all music: could this be a factor? If there was an alternative to itunes I could use easily and still retain my ipod I'd buy it today.