12 Replies Latest reply: Jul 29, 2009 6:41 AM by Fuller42
auntmarching Level 1 Level 1
I've been trying to sync my iPhone recently but get a message that it is synced with another library. That is very unlikely since I've never connected my device to any other user account or computer. I'm assuming something went wrong on the most recent update that might have caused this new warning message to appear. I don't mind replacing everything on my phone with this iTunes library but I don't want any other part of the iPhone to be compromised. Forgive me if this is a silly question, but will erasing the contents of the iPhone with the "new" iTunes library affect other areas or just the music and apps? Thanks in advance.

MacBook, Mac OS X (10.4.11)
  • Jason L Community Specialists Community Specialists
    Hi auntmarching,

    Replacing the music on the iPhone will not completely erase the contents of your iPhone.

    This article: http://support.apple.com/kb/HT1296 provides more information about what can be synced from one library and what can be synced from multiple computers.

  • auntmarching Level 1 Level 1
    Thank you for the quick reply, Jason. I figured it wouldn't affect other areas of the iPhone, but I guess I just needed some reassurance. Any idea why I'm being told that my iPhone is synced with another iTunes library?
  • michelle.behr Level 1 Level 1
    This is happening to me, as well. After the most recent update to iTunes on the mac, syncing now gives the warning that the phone is synced with another itunes library... but that's not the case.

    I'm telling it to sync my videos, apps, ringtones, and music... I really hope that it doesn't erase my address book!!! How do I backup my address book now?
  • Allan Sampson Level 10 Level 10
    As already provided, replacing iTunes content on your iPhone will not erase or touch any other content on your iPhone.

    In regards to contacts, the iPhone is designed to be synced with a supported address book application on your computer. With a Mac, this can be with the Address Book application, which is selected under the Info tab for your iPhone sync preferences.

    Are you currently syncing contact info with the Address Book application on your Mac?

    Contact info on your iPhone is also included with your iPhone's backup, which is created and maintained by iTunes and updated if needed as the first step during the sync process if any of the data on your iPhone that is included with the backup has changed since the last sync.
  • Mike in SRQ Level 1 Level 1
    I don't recall syncing my wife's phone with any other iTunes library. But I too am getting the same message: "The iPhone "xx" is synced with another iTunes library. Do you want to erase this iPhone and sync with this iTunes library?". I don't want to erase the apps my wife has downloaded, but would like to sync selected playlists from our iMac to her phone. Are apps considered iTunes content? If so, is there a way to back up the apps on her phone so I can restore them if I "Erase and Sync"?
  • Allan Sampson Level 10 Level 10
    Apps are considered iTunes content since apps are stored in your iTunes library. Apps purchased/downloaded with the app store on the iPhone should be transferred to your iTunes library the first time the iPhone is synced with iTunes after doing so.

    Apps are not included with the iPhone's backup. 3rd party app settings and data created and stored by a 3rd party app is included with the backup. If these apps are not in your iTunes library, you can re-download the apps with iTunes on your computer and you won't be charged again for any paid apps as long as you use the same iTunes account to re-download the apps that was used to purchase the apps originally.
  • Mike in SRQ Level 1 Level 1
    Thanks Alan,
    How can I tell what iTunes library my wife's iPhone is syncing with? And how do I change it?

    She purchased some music and downloaded some apps using my iTunes store account before we connected it to our iMac. I connected her iPhone, opened iTunes on our iMac and synced, but there are still no apps visible in the "Applications" library.

    I'm willing to re-download the apps, but want figure out how to sync correctly with the iTunes library we use on our home iMac.
  • Allan Sampson Level 10 Level 10
    You're welcome.

    How many iTunes libraries and iTunes accounts do you have on this Mac?

    The iTunes account that is available on the iPhone for purchasing music or apps is the iTunes account that iTunes is logged in with when the iPhone is synced with iTunes. Which computer has she synced her iPhone with and under which iTunes account?
  • Mike in SRQ Level 1 Level 1
    This is exactly why I'm confused. I thought I only had one iTunes library, and have only set up one iTunes account.

    Now, my understanding is that iTunes created a new library every time you install a newer version of iTunes so I think I may have several libraries. But I have never changed back to an older library (knowingly). I'm currently running iTunes 8.1.1. All the music in my library has been purchased with the same login that my wife used to purchase music and apps on her phone. I thought this was the same library we were syncing with - but apparently that is not the case.

  • Allan Sampson Level 10 Level 10
    When iTunes is updated, the iTunes library is updated along with a Previous iTunes Libraries folder created within the iTunes folder. If you check the size of the former iTunes library files within this folder, they aren't anywhere close to the overall size of your iTunes library, and cannot be reused by iTunes after iTunes is updated. Above the Previous iTunes Libraries folder is the iTunes Music folder where all music and video is stored, and the Mobile Applications folder where all 3rd party apps are stored.

    Something else has gone wrong with her iPhone.
  • Mike in SRQ Level 1 Level 1
    Okay, thanks Allan. I appreciate you help.
    I'll check out the iPhone threads now.
  • Fuller42 Level 1 Level 1
    I am having a similar problem to this, and unless I have misunderstood the answers so far there is somethng I'm still not sure about!

    I have been getting the same message, If I press that button to 'erase and sync' that we have been seeing - what will actually be erased?

    My contacts and calenders dont matter, as they are mobileme'd up, my music doesnt matter as there currently isnt any -

    but will my apps be erased or not?
    and what about all my general set up and settings of the iphone (3GS 3.0)

    I just want to be able to put my music onto there from my laptop, without losing everything else I've done on the phone so far!