Weird font and personalization issues after september update

Hey we got the same issues!!!!

Windows 11 25H2: Display language reverts to English and system font is degraded after a cumulative update, here is how I fixed it

After installing the cumulative updates on Windows 11 25H2 (build 26200.9457or 26200.9711 , several machines in our fleet hit the same issue. On standard user accounts only, the display language and keyboard layout switched back to English, the region changed to "World", and the system font was degraded across all applications. French was still listed under the language settings, but without the "language pack" label. Recreating the user profile only fixed it for a few days.

Here is what I did, in this order:

I reinstalled the French language pack (fr-FR) using the files extracted from the Windows 11 25H2 "Languages and Optional Features" ISO.

I restored the user's language settings to French from their own account: display language, language list, keyboard, regional format, and France as the region.

I cleared the font cache from an administrator account. I stopped the Windows Font Cache service, deleted the file C:\Windows\System32\FNTCACHE.DAT and the contents of the folder C:\Windows\ServiceProfiles\LocalService\AppData\Local\FontCache, then restarted the service.

I rebooted the machine.

After the reboot, the language, keyboard, and font were back to normal. Hope this helps anyone running into the same problem.

Hope that this will help you :)