Dr. Web is a Russian anti-virus utility that comes bundled with Plesk. It’s good and it tries to keep the bad guys out.
To keep up with all the mutations out there it tries to update itself frequently but usually doesn’t succeed because the Dr. Web server is busy or down or somehow now working as it should be. Sadly this means that every time something goes wrong I get an email once every hour… imagine what this means when you have 11 servers to look after: an overflowing inbox.
Here’s the solution: tweak a system file and divert those emails to nowhere:
Have a look at either
/etc/cron.daily/drweb-update
or if that file doesn’t exist on your system take a look at
/etc/cron.d/drweb-update
The content of this file should only be one line which calls the actual update routine in crontab format:
#cat drweb-update
*/30 * * * * drweb /opt/drweb/update.pl
Now take out your favourite text editor and amend it to
*/30 * * * * drweb /opt/drweb/update.pl > /dev/null 2>&1
Case closed. No need to reboot your server either.
Special thanks to Igor and igraf on this Parallels Forum Thread.

