I recently moved from a first generation (early 2006) MacBook Pro to a used mid-2009 model using Migration Assistant, with a FireWire cord. It went quite well, with all my settings and hardware moving to the new computer. However, when I tried to sync my phone in iTunes for the first time, it did not show up at all in the sidebar. Here are the things I tried to get it to recognize the phone: authorized the new computer to use iTunes; made sure my OS X 10.6 was completely updated; changed syncing cables and USB ports; unintalled and reinstalled iTunes; and restarted the phone. I finally restarted the phone under DFU, reset it to factory settings, and restored it from a backup I got from the old computers. iTunes then began seeing the phone in the sidebar and even syncing again! I thought I was out of the woods, and the phone was syncing fine all last week. However, I tried syncing again today, and iTunes was not recognizing my phone again. Nothing was there in the sidebar! I shut down and restarted my phone, changed syncing cables, and switched USB ports, and still nothing. I don't want to have to restore my phone over and over or drag it out to the Genius Bar every time; I work full time and don't have time for that. Particulars mid-2009 MacBook Pro with OS 10.6.8, iPhone 4 with iOS 4.3.3, latest version of iTunes (10.3). Another note -- my entire iTunes playlist is on a Toshiba external hard drive. I have been using it this way for nearly a year with no trouble before migrating to the new computer. iPhone never has been jailbroken. What could have happened? Any suggestions?