I was having trouble syncing iTunes to my Apple TV (this is after I have been syncing for a number of months). All of a sudden, iTunes would crash during the synchronization with Apple TV. I tried limiting what was being synced (unchecking Movies, TV Shows, and Photos). Nothing was working. Turns out Genius is to blame…
After a lot of scouring of various forums, I came across a suggestion to delete the Genius playlist from the Apple TV. This made sense to me, as we do have a Genius playlist on the Apple TV (although we have been using it for some time with no problems syncing).
To delete the playlist, go to Music > My Music > Playlists
Arrow down to Genius and hit the right arrow. A small blue trash can icon should appear. Click the center button on the remote to delete the playlist.
Now iTunes should sync again.
Apple TV version: 2.3
iTunes version 8.0.2 (windows)