GPG Mail: Recipients cannot read encrypted mails after migration to Microsoft365

mm's Avatar


05 Sep, 2023 09:09 AM

Which of our tools is giving you problems? We are using GPG Mail (version 7.2) on our MacOS systems (13.5.1) with MacOS Mail.

Attach a screenshot of the version info for all installed components (how to: See "mailview.png" as attached file

Describe your problem. Add as much detail as possible.

Until recently, we had our mail account hosted at some cloud provider ( provided IMAP, SMTP). This allowed us e.g. to send encrypted emails to recipients and them to decrypt our mails e.g. in Outlook on Windows using the Outlook GPG plugin.

Now we have changed our mail provider to Microsoft 365 - keeping the same email addresses and gpg keys. Sending and receiving emails still works perfectly well.

However, several recipients of emails report that they no longer are able to automatically decrypt emails sent by us. Within e.g. Outlook they are just shown the encrypted file "encrypted.asc" - although they were previously able to automatically decrypt and read the mails using the Outlook GPG plugin. Note that the gpg signatures and mail addresses used did not change.

What did you expect instead

I expected that users should be able to automatically decrypt and read emails from us as before.

Describe steps leading to the problem.

See above: We migrated to Microsoft 365 and use the mail account now via Exchange.

Are you using any other plugins?


  1. Support Staff 1 Posted by Steve on 06 Sep, 2023 09:41 AM

    Steve's Avatar

    Hi mm,

    welcome to the GPGTools support platform. Sorry that GPG Suite is causing problems for you.

    Sadly MS Exchange is known to cause all sorts of trouble.

    Could you send a test email our way please? Public key is at

    From what I understand, decryption in GPG Mail is working as expected, even with the O365 setup?

    Which plugin and version of that plugin are you using in the windows Outlook mail client?

    If there is trouble with decrypting using the GpgOL plugin for Outlook, please see their website about obtaining support. There are various resources like mailing list as well as user forum.

    If you find a solution, it would be great if you could crosslink the Gpg4win thread, so other users running into a similar issue will quickly find the solution.


  2. 2 Posted by mm on 06 Sep, 2023 09:58 AM

    mm's Avatar

    Hi Steve,
    thanks for reaching out to me.

    Here are my responses to your questions.

    - test email: in the meantime, you should have receive my encrypted and signed email
    - yes, decryption in GPG Mail is working perfectly fine - before and after the O365 setup
    - Windows Outlook: I installed gpg4win - and also our recipients seem to be using this; it is the current version 4.2.0
      to be honest, I don’t know the exact version number used by our communication partners

    Some extra information: yesterday, we tried sending encrypted mails to someone who is also using O365 but uses emclient as a mail client. He reported the same problem ….

    Yes, I will try to have a look at the gpg4win support forum.

    Anyway, thanks a lot for the moment.

    Regards, Max.

  3. 3 Posted by mm on 07 Sep, 2023 06:24 AM

    mm's Avatar

    I also created a ticket at the gpg4win support forum.

  4. Support Staff 4 Posted by Steve on 08 Sep, 2023 05:15 PM

    Steve's Avatar

    Hey Max,

    thanks so much for cross-linking the gpg4win forum discussion and your thorough follow up with them.

    This is and open PR on GPG4win side is

    Lets hope a release on their side is not too far away.

    Sidenote: really unsure why MS Exchange keeps tampering with encrypted and signed emails. It has been doing that for years.

    All the best,

  5. 5 Posted by mm on 09 Sep, 2023 12:44 PM

    mm's Avatar

    Hi @steve,
    thanks to you for your hint to create a ticket at the GnuPG/GPG4win side. To be honest, initially, I did not think that it could be a problem at their side but I am happy that a solution is under way.

    Thanks also to you and the whole team for providing us such a wunderfull software with gpgtools and your instant support!!!

    Ah, final question: should we close this ticket or wait until a fixed version of GPG4win has been provided?

    All the best, Max.

  6. Support Staff 6 Posted by Steve on 13 Sep, 2023 11:44 AM

    Steve's Avatar

    Hey Max,

    lets close the discussion as there is nothing actionable on our side.

    Note that you can re-open anytime and I would appreciate that very much, if you'd let us know once the fix has made it into a stable release of GPG4win.

    Have a great day,

  7. Steve closed this discussion on 13 Sep, 2023 11:44 AM.

  8. Steve re-opened this discussion on 22 Dec, 2023 08:16 AM

  9. Support Staff 7 Posted by Steve on 22 Dec, 2023 08:16 AM

    Steve's Avatar

    Just a quick update on this as I ran into the open GnuPG issue again and they have a beta version in testing including a fix at:

  10. Steve closed this discussion on 22 Dec, 2023 08:16 AM.

Comments are currently closed for this discussion. You can start a new one.

Keyboard shortcuts


? Show this help
ESC Blurs the current field

Comment Form

r Focus the comment reply box
^ + ↩ Submit the comment

You can use Command ⌘ instead of Control ^ on Mac