I tried on the Apple forums with no luck, so maybe this might prove to be more helpful. If you want the full story, just check here: https://discussions.apple.com/message/17860120#17860120 Otherwise, in bullet points: Reformatted laptop. Forgot to back up iTunes files. Connected iPhone 4 to laptop after reformat and realised that it doesn't sync with my "new" library. Tried de-authorising all computers and then re-authorising this compute to see if I could sync it - didn't work. Tried backing it up and transferring purchases - didn't work. If I sync it with the "new" library, does that only apply to music? I fear that my text and email messages, contact info, apps, app data, photos, etc. will be lost in the process. I don't trust the back ups that iTunes has made since the folder is only 3GB big (unless this is the average size) and by the fact that the phone hasn't properly synced with iTunes since the reformat. For all intents and purposes, my "new" library which was in my "My Music" folder is exactly the same as my "old" library from before the reformat. Can anyone help? Or at least allay my concerns about what data may or may not be lost. Ideally, I want to be in a situation where I can sync as if nothing had happened.