I hate to be the dude who bumps his own post, but it's been 2 months and I still haven't figured this out. Searching for answers online reveals solutions that are more confusing than helpful.
I think you have to associate the iphone with that particular computer, via formatting it(?). My itunes always wants to erase and install my backup on the phone because I last updated it on my old macbook. I just havent taken the time. You do get one free apple tech support call with every iphone/ipod, try that out?
@B0HICAH: yeah, generally you can only associate one library with a device.
I think this guide will take you through, step by step.
When you plug in your Apple device to your new computer that's synced with your old computer, you probably get the "erase and sync" message.
Library Tunes will discover your old computer's iTunes Library ID (from your Apple Device) and apply this ID to your new computer's library. By doing this, you should be able to put new media files on your Apple device using your new computer. You should also be able to transfer purchases from your Apple device to your new computer's iTunes library. For non-purchases, you can use a some free progarm.
Library Tunes will create a backup of your new computer's library just in case. There's a chance there's nothing in your new computer's iTunes library yet, so nothing to lose.
Again, I have to mention by advocating the use of Library Tunes, although it is a free program, I may receive compensation.
Or you can simply use the MobileGo for iOS to help you get the work done.
There are full instructions about how to Sync iPhone to New Computer without data loss.
I hope these can help you !! Good Luck.
Hope I'm not hijacking - I want to be sure I can connect my friend's iPhone 4 (never been updated) to a new installation of iTunes without losing ANYTHING from the auto-sync.
If I install iTunes, authorize it, disable sync, and then connect her phone, nothing will be deleted, correct? Then I should back up, re-enable sync if need be, and then update or do whatever from there?
Just as you dragged and dropped Music, Movies, etc, drag and drop all of your Applications (and other purchased content) onto that external storage. Drag all that to where it goes in to the new iTunes as well.
Pictures, if you have any, can be dragged out of iPhoto or the Pictures folder, and onto external storage. From there just drop them into My Pictures or wherever you'd like on the new computer.
When you connect your iPhone to the new computer, all of your things will be there, somewhere, and you just have to point your iPhone to them. It will wipe your iPhone, inevitably, as you go to a new computer with a new iTunes Library. The only work left is to go through and check what you do and don't want synced to the iPhone when it's connected.
Here's how I sync iPhone with new computer:
Open up iTunes. Plug the iPhone into the new computer, and ensure it is tied to your iTunes account by clicking Store -> Authorize This Computer.
Right click on the iPhone, and select "Transfer Purchases"
If you haven't done so already, move the iPhone backup file into the correct location on the new computer, right click on the iPhone through iTunes and click "Restore from Backup".
For non-purchases, use other apps like FonePaw iOS Transfer.
The FonePaw IOS Transfe is useful! At least, it works well and it's easy to use. I followed the guide about how to sync iPhone to new computer, but it's really simple to use, you might not need the guide. There are some useful tips and tricks on their website as well.
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