Some of my contacts use X.509 / MIME. When I receive mails from them, the little lock icon shows up in the mail list, but otherwise (either inline or in a mail window) there is just empty space and the "Unsicher"-? icon in the ribbon.
You are running in a codepath that means "Outlook told us this was S/MIME, but we have not seen the proper message headers and neither does the data look like it is S/MIME."
Sadly your log does not help much in that case because it marked the mail as bad and aborts.
I've changed that "marking a mail as bad" so that future logs will be more helpful and that it will still try to treat this case as "encrypted" maybe that will already work, although I doubt it. The log will at least be a bit more helpful.
A version with that change is: https://files.gpg4win.org/Beta/gpgol/2.3.3-beta6/
It would be a great if you could ask your contact if they would be willing to help, I think their crypto solution does something strange here.
Here is my S/MIME Certificate chain for "firstname.lastname@example.org"
Thanks, from that log I can understand the problem:
mapihelp.cpp:change_message_class_ipm_note_smime: content type is 'application/ms-tnef'
^ This means that the S/MIME message is wrapped in Microsofts proprietary attachment format. We have code already for that case in the OpenPGP case because that happened with PGP/Inline sometimes, too ( T3419 ). But we didn't have it for S/MIME yet. I thought for S/MIME that would not happen because S/MIME is already always an attachment. I'll add something. The current code is not so good as it will try to decrypt anything that Outlook says is S/MIME but which we do not understand. So a signed only message wrapped in this format would probably fail.
This is a new bug, I believe, but perhaps it only appears with "broken"
S/MIME-messages of this type, So I'll first post it here:
If the newest mail in the Inbox (Outlook 2013 with Exchange Server) is
such a mail, Outlook will not start. It just has the opening splash
window with animation. Nothing behind that. If I kill a gpg...exe in the
TaskManager, the GPG password window appears. After entering the
password, Outlook can be opened again.