Apple’s iOS 4.2 firmware update hasn’t been officially released for too long and already users are having some issues with it. While the update introduces some new features, some users have experienced problems such as all the music from the iPhone or iPod touch disappearing. When launching the iPod app, some users found that the music library no longer exists. Apparently this bug doesn’t actually delete your music library; rather it just doesn’t show it (which is still bad enough). Fortunately, the folks out there have found a solution to the problem. Apparently you’ll need to hook your iPhone up to your computer, play a song that you’ve selected from the phone, and sync the device again, and it should work. Have you experienced such an issue after updating your iOS device? Let us know via the comments section.