Basically iTunes is not syncing all my music to my iPhone. It syncs maybe 500 out of the 4,000 songs I have, then it random says "canceling sync". I own all the content in iTunes and my account is authorized. I've tried everything I could think of. Restoring the iPhone or setting it as a new device. I've tried the whole manually managing music and I've made sure in the music tab that it knows to sync all the music. So why isn't it syncing?! No one seems to have a clue. Something worth mentioning is that the day that it started acting weird was the same day I upgraded to iOS 5. However, that same day I downloaded a program called Spotify on my mac which is kind of like iTunes but for social networking. Is there a way that somehow that program messed around with my "local" files and made it so my iPhone couldn't sync that stuff? I've uninstalled that program but I still can't sync all my music. Please help me!!!