I have reinstalled my macbook pro and now when connecting to itunes, i get a message: ipad can be synced to only one itunes library, do you want to erase your ipad and sync it with this itunes library ? I definitely do not want that. How to copy the whole ipad content to the new itunes library to start using this itunes as a new syncing medium ? I did right click on the devices - my ipad and selected back up, it did something, yet I get the same message again and the content of my ipad is obviously not in itunes. Seems like a strangely stuck process. But I hope we are not supposed to stick to one itunes library forever ?

I moved this to the Help section, as I thought it might receive better attention there. Hope that was OK.

Tim

It seems it is possible, but I have had problems with this before....Have a look:
How to open an alternate iTunes Library file or create a new one

Apples official take on the subject!

This does not help : I can create a new iTunes library, but that's all ... The same message about erasing the iPad comes. Can't believe that. It is quite natural that one sometimes changes the computer or reinstalls something. Does it mean that I cannot backup and manage my iPad any more without erasing it and starting loading and installing all the things, settings, preferences etc again ? I have about thousand ebooks there sorted in many categories, many applications, email/web settings etc. I can't imagine to do all this again. This is unbelievable ...

Originally Posted by Ivo

This does not help : I can create a new iTunes library, but that's all ... The same message about erasing the iPad comes. Can't believe that. It is quite natural that one sometimes changes the computer or reinstalls something. Does it mean that I cannot backup and manage my iPad any more without erasing it and starting loading and installing all the things, settings, preferences etc again ? I have about thousand ebooks there sorted in many categories, many applications, email/web settings etc. I can't imagine to do all this again. This is unbelievable ...

What about making a physical copy of your library using DVD's, then try transferring it to the new or alternative location? I have not tried it myself, but it should be as easy as inserting the media after you have made the copy.

I have a feeling that Apple may not want us to do this, but it does seem a bit unfair.

Others may know more

This will work if everything you want to keep is on the iPad, or you've already got your iTunes library working on the new machine. If not, then you'll want to solve that problem first.

First, in iTunes on the computer, got to the Store menu and authorize the machine. Then go ahead and login to your iTunes account by clicking on the sign in link at the top right.

As a precaution, open preferences, go to the Devices tab, and turn off auto-syncing. This should prevent iTunes from syncing before your ready, and causing you to loose some content.

Now connect your iPad.

When you get the erase/sync dialog, there should also be a Transfer Purchases option. Choose that. If you do not get that option, cancel out of the dialog, right click on the iPad in he Devices list and choose Transfer Purchases. Alternately you can select Transfer Purchases from. . . under the File menu.

When it finishes (this may take quite a while, depending on how much stuff you have on the iPad) make sure all your stuff got transferred. If not try the Transfer Purchases option again. On rare occasions, or when it gets interrupted, not everything will get copied.

That should put an end to the dialog about erasing your iPad.

Now go through all the sync settings for the iPad in iTunes, and make sure they are set the way you want. Note that if you have been syncing photos into albums, and that the sync is turned off this will remove them from the iPad. If those pictures must be recovered because they are no where else you may want to hold of syncing the iPad until you recover them back to the computer. If you have other copies, or were syncing with iPhoto, then just set it how you want.

Be careful about how the apps get synced. If you accidentally delete an app from the iPad all the documents, settings, game progress, ect associated with that app will be deleted too. You can get the app back, but until you've done a back up you can't get that stuff back.

Come to think of it, now is a good time to do a backup. Right click on the iPad under the Devices list and choose Backup.

Now, go to where the backup file is stored and make a copy. Because syncing always does a backup, your first sync will overwrite this file and defeat the whole purpose of this backup, which is to make the iPad recoverable if your first sync messes things up. Here is a link on where you can find the backup file for various OS's. You'll find it under the About Syncing and Backups section:

iPad: About backups

Since you have a Mac, I'll just say Time Machine is your friend. You don't have to have it on all the time. I keep a calendar reminder to do a manual backup every two or three days, which is good enough for my needs.

When you have everything set the way you want, and have confirmed that all your media is in iTunes (on the computer), or safely duplicated elsewhere on the computer, go ahead and sync.