Exim configuration error in line 438 of /var/lib/exim4/config.autogenerated.tmp: error in ACL: unknown ACL condition/modifier in "spam = debian-spamd:true" root@sh1:/etc/exim4# dpkg-reconfigure exim4-config 2015-10-25 14:09:40 Exim configuration error in line 438 of /var/lib/exim4/config.autogenerated.tmp: error in ACL: unknown ACL condition/modifier in "spam = debian-spamd:true" Invalid new configfile /var/lib/exim4/config.autogenerated.tmp, not installing /var/lib/exim4/config.autogenerated.tmp to /var/lib/exim4/config.autogenerated The one stumped be for a bit but the solution - at least on a Debian based system - is to ensure you have installed 'exim4-daemon-heavy` instead of the light packages, aptitude install exim4-daemon-heavy . If this has helped comment of follow me @danielsokolows .