I had installed and used gpg4win 4.4.0 for a short while, then did not use it in a while. When trying to start it again, I only got this popup message (German):
I downloaded it again and installed it again, and that seemed to fix the issue, but isn't it strange for a file to disappear?
The only operations done were installation of Windows updates and installation/updating a few unrelated programs like backup software and video editing software.
The wonders of Windows! Who knows which overzealous component of Windows deleted this file. I suspect that your virus scanner wrongly suspected the file to be malicious (false positive) and removed it. Kleopatra certainly doesn't delete any of its files itself unless you uninstall it. Since a reinstallation (as proposed by Windows likely because vanishing files is a common problem on Windows) solved your problem I'll close this ticket as resolved.