The latest update of iTunes for Windows causes considerable problems: Version 184.108.40.206 crashes after starting or refuses to work, as affected users report. An error message in English then indicates that files are supposedly missing and prompts you to reinstall (“iTunes cannot run because some of its required files are missing. Please reinstall iTunes”).
iTunes only runs in US English
However, you can save yourself the need to reinstall iTunes version 12.12: The problem is obviously related to the language setting chosen for Windows: If the operating system is used in the “English (United States)” language, iTunes 12.12 runs without problems, which is why the bug apparently not discovered by Apple in time for the release. In other languages such as German, Italian, Spanish, French and even “English (United Kingdom)”, however, iTunes crashes or at least cannot be executed. as users found out in Apple’s support forum, among other places.
Apple now seems to have partially reacted to this: In the Microsoft Store, it is currently listed as “not available” for some Windows 10 users, but for others the update was automatically installed by the store on Wednesday lunchtime, so that iTunes can no longer be used is.
Workarounds up to the Apple fix
If you have already installed iTunes 12.12, you can now try to revert to an older version and use the installer from Download Apple directly or use Apple’s software update in older Windows versions (if available).
If the downgrade fails or the problem persists, the Windows system language can be temporarily changed to English (United States) in the language system settings as an emergency workaround. Then you can at least use iTunes again to do a local backup and then install iOS 15 or iPadOS 15 wired. Apple will probably deliver another update for iTunes 12.12 in the foreseeable future, which will fix the language bug.