McAfee VirusScan On Delivery Email Scan Policies must be configured to decode MIME encoded files.

Email has become one of the most frequently used methods of spreading malware, through embedded HTML code and attachments. User awareness and training, warning users to not open suspicious emails or email attachments, and not clicking on hyperlinks, etc. from unknown or known senders, will not fully protect from email-borne malware. Mass mailing worms are similar to email-borne viruses, but are self-contained, rather than infecting an existing file. Protecting from email-borne viruses and mass mailing worms by scanning email upon delivery mitigates the risk of infection via email.