Sometimes cron can send out useful messages to help you to debug your scheduled tasks. Sometimes it can destroy your local e-mail server with spam, failed messages, and general crap. Here’s a quick and easy way to fix it:

cd /var/spool/cron
sed -i '1i\MAILTO=""' *

Make sure you get the quotes right (I would copy+paste)! Note, this will disable e-mail notifications for ALL users.

To make sure that you’re not trying to confuse cron, run a check with this:

grep -RH MAILTO=[a-z] *

This will tell you if there are crontabs with existing e-mail addresses set. Use your discretion as to whether you would like to remove these OR the MAILTO=”” entry. I would not recommend leaving both.

To apply the changes, restart crond:

/etc/init.d/crond restart

You should stop seeing spam from cron!