I never had an issue syncing my iPhone4 to Spotify via the USB or WiFi.
I don't know if this might be the reason, but since I've had the the latest iPhone software update, Spotify does not acknowledge my iPhone via USB connection or WiFi.
I've reinstalled Spotify on my PC and on the iPhone. This resulted in the tracks existing on my iPhone to be greyed out and unplayable.
Help, as I've read so many posts and can't find anyone in my situation that could sync, but now cannot.
Solved! Go to Solution.