root@otley:/etc/apt/sources.list.d# apt-get purge dovecot-core
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package dovecot-core is not installed, so not removed
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 dovecot-common : Depends: dovecot-core but it is not going to be installed
 dovecot-imapd : Depends: dovecot-core (= 1:2.0.19-0ubuntu2) but it is not going to be installed
 dovecot-pop3d : Depends: dovecot-core (= 1:2.0.19-0ubuntu2) but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).