When trying to switch to server based clamav scanning, 1. the "Enable ClamAV" Button does not appear, 2. the error message appears, that clamd has to run and virtualmin is unable to activate server based scanning. Also, on the First Start Wizard, Virtualmin states that it cannot configure Clamav on this machine. The Machine is a Centos 7 minimal with all updates.
It turns out that the clamav-server setup is largely broken, even with manual setup. The clamd service and clamd scanner service are named to clamd@.service and email@example.com and are unable to start. There is no /etc/clamd.d/clamd.conf
I don´t want to configure clamd manually like this http://linux-audit.com/install-clamav-on-centos-7-using-freshclam/ shows, because interference with virtualmin internal configuration processes is unknown.
So this is a severe bug especially for hosts with large email throughput.