iTunes cannot run because some of its required files are missing
iTunes on Windows 10 x64, version 21H1 with latest OS updates.
Yesterday I checked for iTunes updates (I was actually looking for IOS 15 for my iPhone) and iTunes asked to be upgraded to version 12.12.0.6; after the upgrade, iTunes didn't start anymore. The error message is "iTunes cannot run because some of its required files are missing. Please reinstall iTunes.":
I tried repairing iTunes; then I tried uninstalling and reinstalling it; then I tried uninstalling all Apple software (as documented here) and reinstalling iTunes. No luck, it always failed to start with the same error.
I also tried using the version of iTunes distributed by the Microsoft Store; no luck with that, too.
As a last resort I tried installing iTunes in fresh Windows 10 VM (same Windows release, 21H1 x64 with latest updates) with no other software installed and no prior exposure to iTunes. It failed to start there too, with the same error message.
Before the upgrade iTunes was working fine.
Windows, Windows 10