Many readers ask us how to sync an iPhone with a Mac - or more specifically, with more than one Mac, or with a new Mac - without erasing the iPhone's apps, music, photos and other data. This feature helps with exactly that. Here are two techniques for syncing an iPhone with more than one Mac without deleting the content.

Every time you plug the iPhone into a new Mac you get a message saying "Do you want to erase this iPhone and sync with this iTunes library?" Apple makes sure you can only sync the iPhone with one Mac at a time. But this feature shows how to sync with more than one Mac.

How to sync iPhone to iTunes without erasing the content: iTunes erase warning

There are two ways you can sync an iPhone with more than one Mac:

  • Use a third-party app such as AnyTrans.
  • Sync the iPhone with more than one Mac by managing your iPhone manually. (This erases the content.)

It used to be possible to trick iTunes into syncing with more than one Mac by copying the Library Persistent ID Key, but this process no longer works. Apple has also tightened up the way manually managing iTunes content works, so it wipes content the instant you click Erase and Sync (rather than waiting). So for the time being it seems that using third-party apps is the way forward if you want to keep any media on your iPhone, or manually managing music if you don't mind starting from a blank slate.

In this tutorial we'll take a look at both methods.

See also:

Updated 5 September with general updates.

Sync iPhone without erasing: Use AnyTrans

How to sync iPhone to iTunes without erasing the content: Scanning files with AnyTrans

If you have music, movies, TV shows or other data on your iPhone that you don't want to lose, and wish to sync the iPhone with another Mac (without wiping the music), then you need to use a third-party app such as iMobie's AnyTrans 4.

AnyTrans enables you to manually manage the content on your iPhone. You can transfer audio, video, photos, books, podcasts and other contents from your iPhone to your Mac (or vice versa).

This is the best option if you don't have a copy of the iPhone content on a Mac. Use AnyTrans to make sure you've got the content on your iPhone on your Mac.

How to sync iPhone to iTunes without erasing the content: Transfer music from iPhone to iTunes with AnyTrans

Follow these steps to transfer music from your iPhone to your Mac:

  1. Download AnyTrans from the website and launch the program. Depending on your Gatekeeper settings you may need to open System Preferences > Security & Privacy and click Open Anyway.
  2. Connect your iPhone to the Mac using the USB cable. Wait for it to connect and load all the content.
  3. Wait for AnyTrans to finish checking your content. This may take a while, depending on how much you've stored on your iPhone.
  4. Hover the pointer over the icon shaped as an arrow pointing to iTunes. The words Content To iTunes should appear. Click it.
  5. Place a tick next to the items you want to transfer. Typically you'll have Music, Playlists, Movies and TV Shows (depending on what is stored on your iPhone).
  6. Click Start Transfer.
  7. Wait for the Exporting Media window to finish processing. Your media is now being copied from the iPhone to your iTunes library.

The media will now be sent to your copy of iTunes. You can now sync your iPhone with the new Mac, or manage your iPhone manually with more than one computer.

Sync with more than one Mac: manage your iPhone manually

The official method of syncing an iPhone with more than one Mac is to manage the content manually. According to the Apple Support website: "When manually managing content, you can add content from multiple libraries to your iPod or iPad. Even when manually managing music."

The only problem is the first install, which completely wipes all of the media from the iPhone. When you click 'Manually manage music and videos' all of the content on the iPhone is removed.

If you do not have a copy of the music in your iTunes Library you should use a service like AnyTrans to transfer it first. Once you've set your iPhone to manually manage music and videos mode you'll be able to transfer music from multiple Macs without getting the alert.

How to sync iPhone to iTunes without erasing the content: Manually manage music and videos in iTunes

Follow these steps to manually manage music and videos on your iPhone:

  1. Connect the iPhone to your first computer.
  2. Open iTunes.
  3. Select the iPhone using the Device menu in the top-left.
  4. Click the Summary option and select Manually Manage Music and Videos.
  5. Click Apply.

You can manually drag and drop the music files, and videos that you want between your Mac and your iPhone.

See also:

How to manually add or remove music and videos to your iPhone

How to sync iPhone to iTunes without erasing the content: Manually manage music in iTunes

When you are manually manually managing music and videos, you need to copy the music tracks, and video files, from your iTunes' library to the iPhone. Here's how to copy the files across:

  1. Attach the iPhone to the Mac and open iTunes.
  2. Choose Music (or another media option).
  3. Drag media to the left of the window.
  4. Drop it on  top of your iPhone (under Devices).

You can now drag items from the main window to this sidebar to add them from iTunes to the iPhone on multiple Macs. You can use the icons at the top to switch from Music, Films, TV Shows and Apps.

Read next: How to sync to iTunes: Sync your iPhone or iPad with a Mac or PC | Fixes for common iPhone syncing problems