Recently the wife installed the latest iOS update for her iPhone 4 (all 600+ MB of it! And people have the misconception that Microsoft software is bloated?). After the update, the Sync on the phone was failing with the following error: “The iPhone cannot be synced. An unknown error occurred (13019)” as shown in the screenshot below.

She did have the latest version of iTunes – not that made any difference. Also, restarting iTunes or rebooting the phone and the machine did not help and the error remained the same. After a quick search online , it seems quite a few others have the same problem.

For her the sync failure was because of the Music (as did most other people with the same issue); but the failure can be in any group (App, Ringtones, etc.) and not necessarily restricted to the Music group. The easiest way to find out the group where the Sync failed is to keep an eye on the Sync status – it will stop in the group wherever it failed and then you will get the above error.

To fix this error you need to stop syncing the group causing the issues and then re-sync it. Essentially, you reset the sync options for that group. At a high level the steps you need to do are:

  1. Stop syncing the group that failed.
  2. Sync the phone.
  3. Re-enable syncing for the group from Step 1.
  4. Sync the phone again.

In the wife’s case, here are the steps I had to follow to stop the Music from syncing to fix this.

Step 1: Select the Device in iTunes (when it is connected of course).

Step 2: On the right hand side, select group which is failing and uncheck the Sync option. For example, choose Music and uncheck the Sync Music checkbox (circled in red). You need to click the Apply button on the bottom.

Step 3: Be warned, when you uncheck the Sync Music option, iTunes will delete all the music on your phone as shown in the screenshot below. Of course you should only do this from the computer where you have all your music. If you don’t then you won’t be able to sync your music back again. Click on the “Don’t Sync Music” button.

Step 4: Sync your phone as usual.

Step 5: Reverse of Step 2 – you select the “Sync Music” option again and click on Apply.

Step 6: Sync your phone as usual and everything should sync up again as you would expect. Of course this could take some time depending on how many items you have in your group.