Since time immemorial (at least 12 years) installing a new version of iTunes on Windows has been a ritual to get around the installer's seeming inability to replace the iPod service.
To successfully upgrade iTunes on Windows 7 (and previously on Win2K and XP) one has to manually terminate all Apple services (iPod Service, AppleMobileDeviceService, iTunes Helper, mDNSResponder) and then be sure to run the installer using the "Run as Administrator" option, even if your login is a member of the local Admin group. Failure to do any of these steps results in "iPod service cannot be installed" late in the installation, at which point the only solution is to cancel, reboot and reinstall.
Lately (12.4) even following all these steps still results in failure to install the iPod Service.
Does anyone have any insight as to why this problem has gone uncorrected essentially since the initial release of iTunes for Windows, and if there is a foolproof way to upgrade iTunes?
Best Answer
The most common source of this error is that Sysinternals Process Explorer is running. Check systray / taskmanager and close it if its running.
https://discussions.apple.com/thread/2776689?start=15&tstart=0