Q: iTunes won't sync my music, movies, ringtones... Anything!

My problem was exactly the same as yours (I have 1289 songs, almost the same amount, pretty scary) and I fixed it too. I just unchecked "Entire Music Library", synced, checked it again and synced again. That's kind of what you did, so thanks!

Thanks pushc6

This has worked for me iOS 8.1.3 and Itunes 11.3, Thanks a lot !!! I Had spent almost 3 days doing reinstall iTunes, downgrade iTunes, Reset iPhone... but finally music and movies and on my phone after hit sync.

I had the same problem, when i updated my iPhone 5c and the new iTunes on my computer. What I did, was turn off the icloud music library, on my phone and then it synced my music successfully.

just figured out what was going on.  in the new update if you go into music and have icloud music turned on it will not sync.