The bug report gives a workaround.
Jul 15 2021
Forgot to mention one thing: after changing my user folder directory I lost all my Outlook contacts. I was able to recover them... make sure you have a backup before attempting this!
Jul 12 2021
I just had the same issue as hurui200320. My user name contains a "ç" and Kleopatra did not start. The Windows event logger reported a crash in libstdc++-6.dll. This was with gpg4win-3.1.16. Installing gnupg 2.3.1 did not change anything.
Apr 15 2021
gpg4win 3.1 has no full Unicode support. You may try to install the new GnuPG 2.3 version on top of gpg4win to fix this problem or wait until we have releases gpg4win 4 which will come with GnuPG 2.3.