I have Sierra on my MPB and the most current iTunes (I have an iPhone 6 running 10.0.2). It seems that my Finder and iTunes won't let me add or play songs I had added years ago from CDs I own. I can go into my Seagate via their web app and listen just fine. For some reason, it seems, Apple devices don't like these items. They can't be re-added. Deleted and tried to re-add an album from my external hard drive (never been an issue before) and it doesn't show. Also, what was already on the phone shows up in the 'Music' app, but won't play and if I look in iTunes in the 'On my device' area, they are listed, but with the dotted circle. The only thing that is consistent is that it has trouble with songs I added via CD.
