Can others reproduce this? 1) Create a Smart Playlist that incorporates Album Ratings (not Song Ratings). For example, 500 megs of songs with 3 star or better Album Rating, filtered by least-recently played 2) Set the playlist to sync to an iOS 5 device 3) Check back after about a day. Does the playlist still exist in your iTunes library? I haven't been able to figure out when it happens. I can't force it to happen by restarting iTunes or syncing my iPhone or iPad repeatedly. But at some point, the playlist vanishes not just from the iOS5 device, but from the iTunes library on my Mac! I can recreate the same Smart Playlist and it happens reliably. If I don't set it to sync to an iOS5 device, it doesn't happen. That is - the playlist continues to exist if I sync it to my iPod Nano, or don't set it to sync to anything at all. If I don't incorporate Album Ratings, it doesn't happen either.