Are you getting a -39 error when you are syncing your iPhone/iPad/iPod Touch?

To get rid of it, you have to delete the ‘optimized’ versions of your photos and force iTunes to re-generate them:
1. Navigate to ~/Pictures/iPhoto Library (~ means your home folder)
2. Right click on iPhoto Library and select Show Package Contents
3. Delete the folder named “iPod Photo Cache”
4. Sync your device again.

iTunes will regenerate the optimized versions of your photos and you will no longer have an error syncing.

Thanks to MacRumors.

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