To disable any checking of file attachments except for viruses, make the following changes in WHM > MailScanner > MailScanner Configuration and then click "Change":
1. Set "File Command =" to blank.
2. Set "Filename Rules =" to blank.
3. Set "Filetype Rules =" to blank.
4. Set "Archives: Filename Rules =" to blank.
5. Set "Archives: Filetype Rules =" to blank
6. To disable checking of zip attachments, set "Maximum Archive Depth =" to 0.
None of the above will affect scanning for viruses in attachments. Virus scanning will be controlled by the rules in /usr/mailscanner/etc/rules/virus.scanning.rules