So, I tried to add some music to my iPhone 4 today and I got a message saying something about: 'An iPhone can only be synced with one iTunes library at a time. Erasing and syncing replaces the contents of this iPhone with the contents of this iTunes library." Does this mean that everything, even my contacts, photos, text messages, notes, etc. will get erased? I have synced and backed up all my important stuff with this MacBook Pro (2011) before, but this is the first time I've tried to add any music to the phone. I know the problem is arising because I originally had this iPhone synced to my old MacBook Pro- that was stolen. Now I'm on my (new) replacement MacBook Pro and I finally got around to adding my music collection to my MBP; and I want to finally add some music to the iPhone so that I can use it like an iPod. But I want to make SURE that I don't accidentally delete my important stuff! Can I get some advice please?