There have been a few requests for this in the past, but so far this feature hasn't been added. Our on-prem Barracuda units choke on any email attachment larger than 20mb. The AV unit can't handle the attachment, the AV service crashes, the CPU climbs to 100%, and the mail queues backup. Can we please get an option to skip AV scanning for attachments over a user selectable size?
I've opened up multiple tickets for this issue and support has no solution for this problem. Their only suggestion is to limit the email size that we accept. Gmail currently accepts emails of 50mb and Office 365 allows emails of up to 150mb so shrinking what we can send/receive isn't a smart solution.