Upgraded to Ubuntu 14.04 - Mail server missing dovecot-lmtp even though it is installed

Question

So I upgraded to Ubuntu 14.04.1 from 12.04 the other day. Easy upgrade process.

Everything worked fine except for my mail server stopped receiving mail. The logs show the mail arrives and is handled up until this:

 Connect to MAILSERVER[private/dovecot-lmtp]: No such file or directory)

Similar error when a user tries to fetch their inbox. All mail is fetched up until the day of the upgrade, no new mail will arrive.

The following is in postfix/main.cf:

 postfix/main.cf:virtual_transport = lmtp:unix:private/dovecot-lmtp

apt-get install dovecot-lmtp says it is already installed. Did a dpkg-reconfigure, no help.

My setup is maintained by ISPConfig if that helps. I already did reinstall though after upgrading to Ubuntu 14.04. Reinstalling ISPConfig fixed every issue with services except mail.

UPDATE: - I overlooked the fact the previous setup was using courier and dovecot was not even installed. ISPConfig or Ubuntu upon upgrading changed this to dovecot, yet dovecot is not installed. With Dovecot installed it doesn't even start or write to the logs (dovecot reload yields errors, dovecot find logs shows me logs which are contain no dovecot entries).

Answer 1

I examined master.cf, not sure what ISPConfig update did and upgrading to Ubuntu 14.04 but it appears to have maildrop and dovecot configured. I've never had dovecot installed. courier-imap is what I've been using. I noticed master.cf also had maildrop configured.

So I did the following:

main.cf:

 virtual_transport = maildrop

Ran command to force delivery of mail:

 postqueue -f

All my mail arrived.

Now what is the issue with using maildrop? It still appears new mail goes through amavisd?