Desync iPhone from old laptop

Firstly; it's very important that you specify what content you have on the device.

Phone can only be synced with 1 media library at a time. Content syncing is designed so that the itunes library replaces whats on the device with whats on the library. The first time you sync with the new library if there is nothing in it it will replace everything on the iphone with nothing (erase.)

So the first time you sync with the new computer you will be doomed to lose everything unless you have all the content on that new computer. Firstly you need to authorize the computer with your appleID so that you will be able to import your itunes purchases to it (http://support.apple.com/kb/ht1420.) The best way to get everything across it to disable automatic syncing (edit > preferences > devices for windows, itunes > preferences > devices for MAC) and then Transfer purchases (http://support.apple.com/kb/HT1848) to this library. Then after you have got everything in there from the summary pane you can click 'manually manage music & videos' and then navigate to the relevant tabs and select which media you want on the device. The first time it will replace everything on the phone but if you have ticked the media in iTunes it should in theory be replacing it with the exact same thing.

Any Content that you haven't purchased directly from the store (CD's etc...) will need to manually be transferred from PC2PC via external hard-drives or networks and then imported into the itunes library.

Contacts/Calendars/Notes etc... behave differently from itunes content - but at ALL times I recommend creating a backup at the same time you transfer purchases just for that added safety net, you can find out how here:

http://support.apple.com/kb/HT1414

Hope this helps...

Make sure your new computer is authorized in iTunes. Disable autosync in itunes, connect your iphone, right click on it in the device list and choose backup.

This will save data, pictures and settings to itunes. See what's included in this backup here: http://support.apple.com/kb/HT1766

Transfer your purchases the same way to copy all apps and bought media from the Store to your computer.

Set up at least one contact and event on your computer to be able the merge your calendars and contacts after your device got wiped during the first sync.

Apps can also be downlaoded again fro free, in case you miss some: Downloading past purchases from the App Store, iBookstore, and iTunes Store

To save other data, heave a look at this article: How to back up your data and set up as a new device

The rest of the data can be restored from the backup you made.

Restoring: http://support.apple.com/kb/HT1414

Music is one way only, from the computer to your device, unless you bought the songs in itunes and transferred your purchases.

There is 3rd party software out there, but not supported by Apple, see this thread: http://discussions.apple.com/thread.jspa?threadID=2013615&tstart=0

I like this answer.

You're welcome 🙂