“After you update to the new OS, if you load the iPod app, you may see a message stating that your currently have ‘No Content’ on the device,” MG Siegler reports for TechCrunch.
“The way to fix it is apparently to plug your iPhone back into your computer, play a song from the iPhone on your computer, and then sync,” Siegler reports. “The process is very quick because it doesn’t actually have to transfer all that music again, it just makes it recognize that it’s already there.”
Full article here.
MacDailyNews Take: This happened to our iPhone 4 units after updating to iOS 4.2.1 and the fix above worked as described. The media is still there on your iOS device, this just seems to jog things. It’s much faster than transferring all of your media again.