Allowing the Synchronization Client to see the iTunes Library

Problem Description

The synchronization client cannot see the iTunes library.

Possible Cause #1 and Resolution 

After iTunes 12.2, the iTunes library is not shared in a way third parties can read it without some additional configuration. To enable this functionality:

1. Open iTunes preferences.

2. Select the Advanced tab

3. Check the Share iTunes Library XML with other applications checkbox

4. Restart the Synchronization client

For more information, please see Apple's article on the issue here: https://support.apple.com/en-us/HT201610