Dovecot / Thunderbird email duplicates

Question

After installing a new system (Ubuntu 10.04.1 Desktop), I copied the /var/mail dir content to the new system and install - same config - dovecot as an Imap(s) server.

To test the new setup, first the .thunderbird / .mozilla-thunderbird where copied to the new system / same user name (same uid) and Thunderbird was installed.

After a while, Thunderbird downloaded twice the number of emails (300 -> 600), built again its index, then started to download another 600 (double) emails, making it x 4.

My iphone using the same Imap server got also new messages notifications for the duplicates.

So, I wonder if the problem would come

• from Thunderbird while rebuilding its indexes (creating new mails replicated dovecot side)
• from dovecot, with the mix of old / new data.

My first guess would be Thunderbird, but I cannot be sure, and don't want to let the mails being doubled continuously (well, after the night the FS would be full...).

"hoping" someone got a similar problem to be shared... thank you.

Answer 1

I will answer it if it can help. It seems the problem was rather dovecot side, which had a hard time to deal with indexes from the previous server. What I did to fix the problem was

• recreate a new /etc/dovecot/dovecot.conf based on the new server version
• clean users indexes (mbox mode still had the /var/mail content untounched and available)
• clean Thunderbird indexes as well

Restarted the whole, old messages were downloaded again, and no more duplicates.