Thunderbird cannot search PGP-encrypted emails. Hence, I was considering copying all my emails from IMAP to local storage, then decrypting them all locally, so that they are searchable. Is this possible?
Thunderbird stores email folders as a single mbox file. I attempted
gpg -d mbox_file, but this only decrypted a single email, and then failed with an error as follows.
gpg: [don't know]: invalid packet (ctb=46) gpg: decryption failed: Bad signature gpg: packet(3) too short
N.B. the mbox also contains non-encrypted email. I could perhaps filter these out from within Thunderbird, but the solution would preferably deal with this elegantly.