I recently upgraded to the iPhone 5. At this time, I also changed what computer that I synced my phone as I had been using an older machine.

Everything works fine, except I am unable to sync my music to the phone as iTunes says that this phone is synced with a different iTunes library and do I want to erase it and sync with this one. I have never synced the 5 with another machine, I I guess it is seeing that I I backed up and restored my from my iPhone 4, which was never synced to the new machine.

Must I actually erase the phone and resync it, and if i do so will this affect my App purchases?

Thanks

Craig