Microsoft Exchange proactive scanning can be enabled on Mailbox servers. With proactive scanning, Mailbox servers that contain public folder databases scan files as they are posted to the server. Proactive scanning also scans messages in the Sent Items folder in mailbox databases.

By default, proactive scanning is disabled. However, because content posted to a public folder database is usually not routed through a Hub Transport server, in order to ensure that the content is scanned, it is recommended that you enable proactive scanning for public folder databases. Scanning material as it is posted to the public folder database also prevents download delays when the content is accessed.

You can enable proactive scanning in one of the following ways: