4/1/22
I see same symptoms when opening a mail in thunderbird 2 or 3 weeks after I received it, without moving it in another folder. But using "repair folder" in TB, I get it back, so for me it looks more like a TB cache problem.
I've still not managed to solve for this problem; 'repair' doesn't fix it.
Anyone here have a reliable fix -- either on the TBird &/or Dovecot sides -- to get these subfoldered attachments openable/readable? Ideally without the need for manual intervention each time?
The issue, again is:
Email with attachments (e.g., pdf) I receive to an account INBOX can be accessed in TBird/Linux with no problems.
Dubl-Click on the attachment, and it opens in app -- e.g. pdfs open in Okular.
Saving the attachment to Desktop,
ls -al /home/pgnd/Desktop/SomeFile.pdf
-rw-r--r-- 1 pgnd pgnd 197K May 18 07:49 /home/pgnd/Desktop/SomeFile.pdf
All good.
If I move the message , including attachment, to any other (sub)folder, and try to open the attahment,
I get the usual open dialog,
You have chose to open:
SomeFile.pdf
which is: Portable Document Format (PDF) (66.7 KB)
from: imap://mx.example.com:993
What should Thunderbird do with this file?
[X] Open with 'Okular (default)'
which, on 'OK', does open Okular -- with an Error:
Error -- Okular
Could not open file:///tmp/pid-59993/SomeFile.pdf
checking
ls -altr /tmp/pid-59993/SomeFile.pdf
-r--------+ 1 pgnd pgnd 27 May 18 07:46 'SomeFile.pdf'
If I move the message BACK to imap INBOX, and open/save attachment it's good again.
Thunderbird is not correctly retrieving the attachment when the message is not in imap:INBOX.