Thanks, from that log I can understand the problem:

Ok, with the beta gpgol the mail is successfully decrypted. This is the debug.log:

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.

3.1.5 is released with this change.

This should work with Gpg4win-3.1.5

Thank you very much for the quick response and try-out in detail!

Bug or user error?

Thanks for reporting your problem. We are highly interested in any crash. But please note that our minimum supported Exchange Version is 2010 because 2007 has reached end of life in april 2017. So I cannot test with that Server.

Default settings in Outlook are as following: (i) S/MIME encryption disabled, (ii) S/MIME signature enabled.

I have a workflow now that does this without the openings. The mail is kept open by Outlook anyway when the properties are changed.

To reproduce it the key is to close Outlook through the file -> close option.

It happens with 3.1.4, too.

A wait, we have T4203 for the continuing problems. So let's close this.

This was likely one form of T4111

This had also something to do with the missing keycache that will be released in 3.1.5 so that sometimes S/MIME keys were not cached internally and so would not be used.

There is still at least one report claiming that this still happens for large attachments. I could not reproduce it.

This was fixed with the Gpg4win-3.1.4 release. Apologies that I forgot to mention a pre release version / installer in this issue.

I've tried to reproduce it but failed. Even If I open the message in a new window or a new explorer the message is correctly caught.

Yes. Thanks! I'm at over 2500 S/MIME verify operations without a crash now!

Yes! Thank you very much. My test runs and my Outlook has verified 2500 S/MIME Mails without a crash.

The T4237 fix should also fix this one.

I'm currently looking at the CloseHandle in _gpgme_io_close:

Btw I've checked that the errors are the same in T4111 and this:

I've seen now four crashes in _gpgme_io_spawn. I've added tracing that shows that the CreateProcess itself is crashing. I do not see how this is possible. I'm printing the command line and the program name in debug output and both look fine.
The command line is also mutable.

I'm also seeing hangs. Sometimes with gpgsm running. Sometimes without it running.

Did you have the chance to try it out with 3.1.4?

There were two ways to access the registry and the config value load did not fallback to HKLM. I've removed the second way and I've tested it and it works now as it uses the codepath with the fallback.

With Gpg4win 3.1.4 and the two blocking options, searching for any name in Inbox, entering more than 2 letters will crash Outlook 100%.

Dear aheinecke,

Hi Adam,

Hi Andre,
thanks for the fast feedback. I will wait for the 3.1.4 Release then and test it afterwards. If it still occurs i will update this thread. Thanks for your help!
All the best
Dorian

Thanks for the report. Prio High as this is data loss. I won't stop the 3.1.4 release which is currently in progress though as this issue does not appear to be a regression.

There is now an option in the debugging tab of the GpgOL config dialog to disable async decryption. This does not fully fix the issue but maybe mitigates it for some users that are very affected by this.

I finally got around to look at your examples. Sorry for the delay. I can reproduce the issue and understand the problem.

Thanks for the report I'll look into it. Won't make it into the next release though as we are currently very close to the release.

It's implemented.

This required some changes in the keyresolver / newkeyapprovaldialog in libkleo, too.

This is done now and can be accessed through the config dialog

I think with this warning and default off I can live with this option as it is now.

rev. 1b37aa01cc67d942de06c882fd9d30d39866b111 turns it off by default and even with it enabled only searches the X509 servers if there is no OpenPGP key for this address already available and S/MIME is not the preferred protocol.

This is how it looks like:

After several experiments with attachment flags to get the same behavior outlook does for unsigned mails I could not find a way to set both the content-id and cause the attachment not to be hidden.

The reason for this appears to be the "Content-ID", this is usually set for embedded attachments like images and not for attachments like PDF's.
This leads to the attachment being hidden, e.g. if you have embedded images you do not want them to show up in the list of attachments.

Turns out that that was not the problem.

In T4111#118259, @JJworx wrote:

That may be true, my Outlook crashes more often. Especially when dealing
with incoming S/MIME-signed mails!

This was a regression from 59e8a7ee3bcd16275091c9535626e49fc2a6c4af where a performance improvement to cache an object caused this problem.