Problem: Worked on a computer where the client installed the newest iTunes update. Once the installation was finished, they got the following error when plugging in their iTouch, iPod or iPhone: “This iPod cannot be used because the required software is not installed…” It then tells you to uninstall iTunes and then reinstall which didn’t work.
Solution: Came across a few suggestions to uninstall both iTunes and QuickTime, then let the iTunes installer install both. I did that along with uninstalling the Apple Mobile Device Support and then reinstalled and everything worked for me. My theory is that uninstalling the mobile device support is what really did it. I would recommend uninstalling that first and move on to iTunes and QuickTime if it doesn’t work.