Q: Damaged song always shown as "downloaded" in account. Need to force download again.

Purchased song on iPod Touch and all songs play on this device. Then later, downloaded in iTunes to my authorized MacBookPro.

One song may have been damaged during download. Before playing this one song, iTunes requests sign in to play. After signing in, iTunes says already authorized to play and then skips to next song. Never plays on this device.

Tried everything, including sign out/in and create MP3 version (errored). To force download, moved file to desktop and deleted this one song from iTunes.

Damaged song always shown as "downloaded" in account. Need to force download again.