Unable to sign e-mails with Thunderbird 78.3.2 and Nitrokey Start in Windows 10

I get the message

Die Nachricht konnte nicht gesendet werden, da es ein Problem mit Ihrem persönlichen Schlüssel gibt. Die konfigurierte Schlüssel-ID 'B7BD0B17C3469587' wurde nicht in Ihrem Schlüsselbund gefunden.

Own translation:

The message could not be sent because there is a problem with your private key. The configured key ID 'B7BD0B17C3469587' cannot be found on your keyring

With GPA or gpg –card-status the access to my Nitrokey Start works.

I have configured:

  • In Thunderbird I have set mail.openpgp.allow_external_gnupg to true,

  • the path variable of my user contains the directory with the GPGME-Libraries gpgex.dll and gpgol.dll

  • In the end-to-end configuration of my e-mail account I have entered the master key as external GnuPG key. The Nitrokey only contains the subkeys for Signing and Encryption.

What must be done? Thank you.

Hi @Alexus9!

It’s even worse in my case - Thunderbird 78.3.2 crashes on an attempt to decrypt the encrypted message draft. I do not know however, whether this is not caused by the email service provider.

For what is worth, I think I have fixed the error you are encountering - in my case by removing spaces from my hexadecimal ID.

  1. My guess is you have not selected the master key, but some other - could you check once again?
  2. Could you check, whether the public key metadata are shown for the gpg --card-status?
  3. Have you imported the public key?

I use Kleopatra under Windows to manage the smart card.
I understand you have used following guide:

Could you confirm?

  1. Have you imported the public key?

That was it!

First of all I wanted to test the simplest case Signing, where only the secret key is needed. But obviously Thunderbird expects the public key in his keyring in this case too.

When I imported the public key, it worked.

Thank you!


I have prepared a quick documentation page stub for this. For now it mainly refers to the Mozilla’s Wiki. In case you would see any important information from that page or encounter any specific problems please let me know. Mentioned page: