Beginning April 6, 2018, we began piloting a product aimed at reducing the university’s exposure to dangerous phishing messages received by faculty, staff, and students. One feature that has been implemented is scanning attachments sent via email. The other feature we have implemented is called "Safe Links."
Initially we enabled an attachment scanning feature called "Dynamic Delivery" that would send you a preview of the attachment as it was being scanned. The actual attachment would be delivered shortly after. Many people let us know that they would prefer not to receive the preview message. Based on that feedback, we chose to disable Dynamic Delivery on June 7, 2018. Now you will receive only the original message with the attachment, once it has been scanned. This means that email messages that include attachments can take longer to deliver. Usually the scanning will add only one or two minutes to the overall delivery time.
The attachment scanning delay can be avoided by saving files to OneDrive, and sharing them from OneDrive. The recipient will receive a link to download or open the file.