$ sudo dpkg -i --force-overwrite mailscanner_4.66.5-1_all.deb
[sudo] password for jason: 
Selecting previously deselected package mailscanner.
(Reading database ... 99213 files and directories currently installed.)
Preparing to replace mailscanner 4.58.9-2ubuntu1 (using mailscanner_4.66.5-1_all.deb) ...
invoke-rc.d: initscript mailscanner, action "stop" failed.
dpkg: warning - old pre-removal script returned error exit status 1
dpkg - trying script from the new package instead ...
No MailScanner found running; none killed.
invoke-rc.d: initscript mailscanner, action "stop" failed.
dpkg: error processing mailscanner_4.66.5-1_all.deb (--install):
 subprocess new pre-removal script returned error exit status 1
invoke-rc.d: initscript mailscanner, action "start" failed.
dpkg: error while cleaning up:
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 mailscanner_4.66.5-1_all.deb
jason@mail:~/Desktop$ sudo dpkg -i --force-all mailscanner_4.66.5-1_all.deb
(Reading database ... 99213 files and directories currently installed.)
Preparing to replace mailscanner 4.58.9-2ubuntu1 (using mailscanner_4.66.5-1_all.deb) ...
invoke-rc.d: initscript mailscanner, action "stop" failed.
dpkg: warning - old pre-removal script returned error exit status 1
dpkg - trying script from the new package instead ...
No MailScanner found running; none killed.
invoke-rc.d: initscript mailscanner, action "stop" failed.
dpkg: error processing mailscanner_4.66.5-1_all.deb (--install):
 subprocess new pre-removal script returned error exit status 1
invoke-rc.d: initscript mailscanner, action "start" failed.
dpkg: error while cleaning up:
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 mailscanner_4.66.5-1_all.deb