> I am finding that Thunderbird 52.5.0 is not displaying PGP encrypted
> mail messages properly. I am seeing two issues:
> I consistently get "Enigmail Error - No Valid armored OpenPGP data block
> found" on various inbound (inbox) encrypted messages. If i open another
> mail client, before touching the mail item in Thunderbird, like outlook,
> where both mail clients are using IMAP, click on the item, see it
> decrypt the mail item in outlook, then move the mouse to another outlook
> mail item, whilst keeping Thunderbird open, i see Thunderbird update the
> (same) encrypted mail item, to now include the missing GPG datablock
> attachment, and then Thunderbird can open and decrypt the message.
> Additionally, with some encrypted mail items, I get the decrypted
> message shown in the main Thunderbird Inbox view, but when I double
> click on the mail item to a separate tab, get an empty tab. Close the
> empty tab and re-open the same message - which then displays the
> decrypted mail item correctly.
> Anyone experiencing these behaviors ?
Thunderbird does things to E-mail messages that might corrupt a message
that is encrypted per the OpenPGP specification. It might be possible
to avoid this problem if both of the following apply:
(1) the message is plain-text and not HTML-formatted,
(2) format=flowed is disabled by setting
mailnews.display.disable_format_flowed_support to "true" and setting
mailnews.send_plaintext_flowed to "false".
In general, however, I send a simple unencrypted message with my
encrypted content in an attached file.