I recently had to reformat/reinstall my computer. I re-imported all my music into iTunes. I then took my iPod 4G, which hadn't been synced in a year or so, and tried to sync it with the computer to add new music. iTunes said it would have to erase the iPod since they didn't know each other, which I expected. iTunes successfully erased the iPod, but now it will not transfer songs to the iPod. I can start the sync, a few files will transfer, then iTunes will stop accessing the hard drive (I have a status light) and will stop transferring data to the iPod. No error is given on either the computer or the iPod. At this point, iTunes cannot be quit (it will freeze if you try). If I force-quit iTunes and reboot the iPod, connecting the iPod again shows that nothing transferred to it. Each time I try, the process will fail on a different song, so I don't think it's a corrupt song file. So far, I have tried restoring the iPod, restoring the iPod on a windows computer, deleting all iTunes-related configuration files and folders in my home directory, and running the diagnostic tests on the iPod. In searching this forum, I haven't found anything like this. All the other problems either have different symptoms or are cured by things I've already tried. Does anyone have any idea what to do here?