Sounds like the old horror stories from years ago when iTunes was very finicky on Windows. I must have had to go through a similar uninstall and reinstall ritual half a dozen times, or more. Fortunately that doesn't happen with Macs, at least not yet. But iTunes does remain a slow dog of an app that needs to be totally reworked. Regardless of computer OS, it is unreliable with WiFi syncing and runs at a snail's pace. Even wired syncing can bog down and even fail. Since iTunes has been around now for 7 or 8 years, you would think Apple could pull its head out of its backside and get it programmed correctly.