When you try to sync your Apple iPhone, you may get an error:
The iPod cannot be synced. An unknown error occurred (13019).
To try to solve this issue, try the following steps:
1. Open iTunes.
2. Select the iPhone under Devices on the left side.
3. Click the Music tab.
4. Under the Sync music area, choose Selected playlists.
5. Uncheck the Voice Memos playlist.
6. Click Apply.
Now try to sync your iPhone and see if it works. If it does, there is obviously a problem with your Voice Memos. Email them to yourself from the iPhone using the Share option so that you don’t lose any data. You can then delete the Voice Memos from the iPhone and iTunes.
This problem can also be caused by corrupt music, applications, podcasts, etc. You may need to track down which type is causing the issue by disabling each data type to see which one is causing the issue.
See also: iPhone OS Error 13019 during sync