If you’re determined to switch back to iTunes 10 but don’t want to lose your library and any assets tied to iTunes on your Mac or PC, be prepared to take a deep dive.
You’ll need to download three packages, one of which is the actual iTunes 10.7 DMG. The remaining downloads are two utilities that will help you inspect the DMG and clean your Mac of any iTunes 11 remnants, respectively. Those are Pacifist and AppZapper.
You’ll also need to have your system backed up before attempting anything, and note that the process is different between platforms – the Windows process is a whole other story.