* Purchased tracks randomly grey out and become non-playable.*<p>This 1000 times.  I&#x27;ve been through three iPhones, and continue to be baffled why some of my music becomes unplayable.  I solve by syncing (again and again...), navigating endless menus and changing random values in a vain attempt to find the problem and then hoping, and praying that next time I&#x27;m in my car, all my music will be available.