Clamav not starting (exim can't find clamav.ctl)
My exim4 process is configured based on this post and other points noted here.
Today it started failing - clamav failed to read its db (locked) possibly due to freshclam runs.
Debian bug gave the hint - the packages in volatile have this fixed (a non-security update that fixes this issue in stable).
So - added to my apt-config:
deb http://volatile.debian.org/debian-volatile etch/volatile main contrib non-free