You've stumbled upon a complicated situation. Apple does not make it very easy to start syncing with a new computer unless you want to completely wipe out your device in the process. This doesn't mean you can't do it. The process is simply less than ideal. First things first, let's take a look at how to solve your specific problem. After that, we'll look at a few ways you can sync with multiple machines.
Switch Your iDevice to a New Machine
Switching your iPhone, iPad, or iPod touch to a new machine isn't fun but it isn't impossible. Just follow these steps:
- Authorize your new computer to use your Apple ID. This is the email address you use to sign into iTunes (and probably anything else Apple-related). If you don't know it offhand, you can just check the computer you're currently syncing with. If you go into the iTunes Store it should appear in the upper-righthand corner. Once you know it, go to the new computer you want to sync with and locate the Store menu. From there, choose Authorize This Computer. (In the event you've switched Apple IDs and made purchases with more than one, you'll need to perform this authorization for every account. See this Apple support page for details.) Connect your iDevice and wait for it to pop up in the iTunes sidebar. Once it does, go to the File menu and select "Transfer Purchases from Hot Carl's iPhone." (I'm just assuming that's what you named your device, but if it's different this option will reflect that.) If your device is full of content, this process may take awhile. Go make yourself one of your famous meatball subs and give it a little while. Now it's time to transfer your other media that wasn't
Senuti will do the same for free, but isn't quite as feature-rich or elegant. If you're running Windows, you can just go into iTunes, select your device, enable disk mode, and open up the disk in Windows. Once you have the iPod open in Windows Explorer you'll need to go to the Tools menu, choose Folder Option, and check view hidden files and folders. This will provide you access to your media. Alternatively you can use winamp's iPod plugin (along with Winamp. of course). Sync your apps from your device to your computer in iTunes by clicking on the Apps tab from your device's page, checking the sync apps option, and clicking "Apply". It never hurts to backup your device so let's make that a necessary step. Right-click your device in the iTunes sidebar and choose Backup. (This should take a few minutes so now's a good time to see what else is on Lifehacker.com .)
Wasn't that tedious and annoying? On the plus side, at least your content is ready to be synced on the new machine. If your content gets wiped on your phone, at least it's safe and sound in iTunes on the new computer you want to sync with so it can be transferred back. Of course you can always just buy iTunes Match and let Apple sync your music for you. (Note: you'll still have to go through the processes above to transfer your apps, videos, and everything else, but at least it'll take care of what is likely the biggest hassle.)
Apple's much-delayed iTunes Match service launched today, bringing their vision of music in… Read more Read more
Sync Your iDevice with Multiple Machines
There are two ways you might want to sync with multiple machines and neither are perfect. First, if you want to sync some content (such as music, videos, and other media) with one machine and different content with another (such as apps and contacts) you can do that easily by just being selective on each machine. On the first machine, connect your device and tell it what you want to sync. On the second machine, do the same but select different options. That means if you tell the first machine to sync music you cannot sync music with the second machine. This has the obvious drawback of being unable to take the same kinds of content from two machines, but if that's not something you need to do then this method should work just fine.
If you just want to be able to sync with any machine, the absolute best method (in my opinion) is syncing your iTunes folder with Dropbox. That link will take you to a very in-depth tutorial that'll teach you the entire process for both Mac and Windows. I've been doing it for almost a year now and it's fantastic. If you don't want to pay for all that Dropbox space, however, check out MediaRover. It's free and will sync everything locally.