Do this, as posted by tt2.
It wont fix your problem but help in troubleshooting, especially if your hardisk is dying and causing all sort of errors.
Had to restore my iPod Classic and now iTunes won't sync. It syncs for a while but then I get an error message. I stop it, start over again and get a different error message. First it says it can't read the folder, then it can't read the file, then it gets an "unknown error (-81)"... what the heck is going on here
To be of any help, can I get these info?
Have a nice day!
2. I'm afraid to plug it back in again to check, but it said that I had the latest version installed...does that help?
3. Yes I've tried that, same thing happens.
Last week after numerous attempts I was able to get it to sync about 3400 songs (out of 22000) before it crashed, today I got up to around 4300 and a new Windows error "Delayed Write Failure" in addition to a couple different iTunes errors.