https://www.bleepingcomputer.com/news/microsoft/windows-11-incompatible-with-apps-using-non-ascii-registry-keys/ > Microsoft is blocking Windows 11 upgrades if customers use applications that create registry keys using some non-ASCII characters. > As the company explains, on impacted systems such apps might be unable to open and could also cause other issues or errors in Windows 11, version 21H2 including blue screens.