Patrick Brunschwig

If you want to decrypt a message sent to yourself you need the same private key in both email clients. Did you import they OpenPGP key you're using in Postbox to Thunderbird?

Sender's Autocrypt key is not imported

I released Enigmail 3.1.8, which fixes the issue. Autocrypt keys are now automatically imported again when needed. Using Enigmail -> Sender's Key -> Import Public Key will not work - such functionality is not intended.

I debugged this and found that Autocrypt doesn't work indeed on SeaMonkey. I'll fix this.

Sender's Autocrypt key is not imported

That's not how Autocrypt works. When you read a mail with an Autocrypt header, Autocrypt keys are automatically imported to a separate database, and assigned to the sender's email address. The key is only imported to GnuPG once you try to send an encrypted mail to the recipient.

gpgme-json looked for even when settings do not require it

Encryption/signing broken, when using GnuPG engine