Installed ITunes11 for 64 bit Win7 yesterday (8Dec12). The update seemed to go well altho I saw some odd behavior and do NOT like the changes that have been made to the interface at all btw -- the new format for browsing the contents of the music library is awful. What I discovered later was MUCH worse and that is when I discovered that my IpodTouch 4G which I had synced after updating to iTunes did not contain ANY of my videos and a mere fraction of my music and no playlists whatsoever. I did manage to get my videos back on by playing the game of checking "don't sync my videos" -- syncing (which ostensibly removed that which was already not there) -- rechecked "sync my videos" -- and then synced -- which DID restore them. I tried various strategems to get iTunes to copy over my entire music library .. managed to get part of it restored .. but no matter what I did .. not all of it. It seems to be stuck on a few tracks that it thinks need to be copied and ignores everything else altho it DOES recognized the existence of the rest of my music library. It just won't restore it to my Ipod .. after it so rudely .. IMHO .. removed them. This applies not just to music but playlists as well. There is something seriously wrong with this major 11.x update. One thing I'm considering doing .. after I return from a week long business trip (where I am no) is to trick ITunes into doing what it needs to do by removing all my music from the iTunes library (not the files -- just the index) -- sync to the iPod -- restore all the music to the iTunes library -- and sync again. THAT -- or Apple produces a big fix to Itunes11.
Based on what I've seen elsewhere in the Forum .. my despair and disgust with iTunes11 is shared by others. Hopefully, Apple tracks these forums given that there seems to be NO true mechanism for getting technical support with iTunes, except in association with an Apple device like iPod, iPodTouch etc.
Btw -- given the hideous experience with the iTunes11 update on my home machine, I will NOT permit the Itunes11 update on my office laptop -- I'll uninstall it if need be..