dpkg -l | grep courier
ii  courier-authdaemon                0.62.4-1                          Courier authentication daemon
ii  courier-authlib                   0.62.4-1                          Courier authentication library
ii  courier-authlib-userdb            0.62.4-1                          userdb support for the Courier authenticatio
ii  courier-base                      0.63.0-2.1ubuntu1                 Courier mail server - base system
rFR courier-imap                      4.6.0-2.1ubuntu1                  Courier mail server - IMAP server
iFR courier-pop                       0.63.0-2.1ubuntu1                 Courier mail server - POP3 server


sudo apt-get remove --purge courier-imap
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  courier-imap*
0 upgraded, 0 newly installed, 1 to remove and 58 not upgraded.
2 not fully installed or removed.
Need to get 0B/66.7kB of archives.
After this operation, 1,671kB disk space will be freed.
Do you want to continue [Y/n]? Y
dpkg: error processing courier-imap (--purge):
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting a removal.
Errors were encountered while processing:
 courier-imap
E: Sub-process /usr/bin/dpkg returned an error code (1)


sudo dpkg --remove --force-remove-reinstreq courier-imap

dpkg: warning: overriding problem because --force enabled:
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting a removal.
(Reading database ... 34334 files and directories currently installed.)
Removing courier-imap ...
 * ERR: config file missing
invoke-rc.d: initscript courier-imap, action "stop" failed.
dpkg: error processing courier-imap (--remove):
 subprocess installed pre-removal script returned error exit status 1
 * ERR: config file missing
invoke-rc.d: initscript courier-imap, action "start" failed.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 courier-imap