Sonicwall – 552 MS-Office file containing VBA macros found inside of the email

We were having clients say that they were unable to send us emails containing VBA macros. After spending at least 45 minutes checking all of our usual suscpects, I finally got a copy of the error message the client was getting, and they forwarded me the following error: 552 MS-Office file containing VBA macros found inside of the email.

At this point it I realized it was not coming from our mailhost. I quick bit of googling and I found that this was being blocked at the firewall level. It appears that Sonicwall firewalls when they have enabled the Gateway AV security service will block VBA macros as an option. It is a configuration option to enable or disable.