After a Debian Jessie update clamav-daemon starts spouting out:

(!)connect to /var/run/clamav/clamd.ctl failed, attempt #1: Can't connect to a UNIX socket /var/run/clamav/clamd.ctl: No such file or directory

To correct, edit /etc/clamav/clamd.conf  and comment out (so that it looks like follows)

#AllowSupplementaryGroups true

And then restart the clam daemon with

service clamav-daemon restart