Please note that I'm also unsure if this issue might also possibly be related with T5593 issue, a part that I'm still in same working environment and so with 'gpg4win-3.1.16.exe' setup completed for 2nd time and left in place. Main difference is that as per my own 'Sat, Sep 25, 10:57 PM' comment my %PATH% system environment variable has already been manually updated via OS UI simpler confirmation only after prepending '%ProgramFiles(x86)%\Gpg4win\bin;%ProgramFiles(x86)%\GnuPG\bin;' into registry Path (so I fully implemented my own suggestion... :-D ).
Anyway, before opening this as a new bug I also verified contents of '%ProgramFiles(x86)%\Gpg4win\share\gpg4win\README.en.txt' and '%ProgramFiles(x86)%\Gpg4win\share\gpg4win\HOWTO-SMIME.en.txt' and quite extensively searched on this system in any previous reference was already existing about effective creation of above mentioned folders during setup.
But since all folders above are already referenced into README.en.txt and HOWTO-SMIME.en.txt I'm also assuming Gpg4win developers might also have liked them to be created.
In addition to this I also used following already known commands (& also referenced in other known references I found: T3378, T4788) :
- 'gpgconf --list-dirs homedir' (which properly resolves in 'C:\Users\<myAlias>\AppData\Roaming\gnupg' and this folder indeed already exists,
- 'gpgconf --list-dirs sysconfdir' (which also resolves in 'C:\ProgramData\GNU\etc\gnupg' but this folder tree does not exist yet) so no '.\GNU' or '.\GNU\etc' or '.\GNU\etc\gnupg' or '.\GNU\etc\gnupg\trusted-certs' or '.\GNU\etc\gnupg\extra-certs' folders were found after my last 2nd 'gpg4win-3.1.16.exe' setup completed in same T5593 error conditions.
So I also hope someone might also be able to confirm here if all folders above will really already exist after 'gpg4win-3.1.16.exe' setup completes without errors.