iPhone 4s sync session failed to start
Got my new iPhone 4s earlier this week. For some reason whenever I restore the 4s from my 3gs backup (running IOS 4.2.1), it won't sync and I get an error saying my iphone can't sync because the sync session failed to start. I restored my 4s and am able to sync just fine after a fresh restore, but once a restore from my 3gs backup - it fails to sync again. I am running iTunes 10.5.0.142 on Windows 7, however I have tried syncing on my sisters macbook pro and get the same error. She has a 4s too and hasn't had this problem though.
Any help would be greatly appreciated.