Music and Ringtones no longer found - Nexus 5 with Lollipop
I ended up trying the following
1) Looking at the logs. Saw no smoking gun
2) Clearing the memory on the media storage. That didn't do it. Wasn't a good idea either. It couldn't see the pictures I had taken after the issue started.
3) Resetting the phone and restoring from backup. That did it. Bit painful.