I use iTunes on a Macbook Pro and my library files and music are stored on a NAS. I have a playlist called "iPhone 6" created to sync specific music to it from my library. For some reason, lately iTunes will create a playlist called "iPhone 6 1" and it will mess things up. For one, after syncing most of my music is missing on the iPhone and I have to resync about 4,500 songs again. Has this happened to someone as well? Thanks!