With a redirected AppData folder [ https://support.microsoft.com/de-at/help/242557/registry-settings-for-folder-redirection-in-windows ] I could reproduce crashes of Kleopatra and a "General Error" when trying to generate a key with Kleopatra.
As far as I can tell GnuPG itself works fine and I was able to generate a key there.
This was also reported in BKO: https://bugs.kde.org/show_bug.cgi?id=389919 and might explain other reports that Key Generation fails with General Error.
Priority High as this appears to be a common setup in Server environments.