After installing Symantec Mail Security for Microsoft Exchange on Exchange 2013, Background Scanning is missing from the list of options under the Scans button.
With Microsoft Exchange 2013, Microsoft no longer supports VSAPI access for third-party Scanners. VSAPI is the method Background Scanning utilizes to perform this type of scan. Since VSAPI is no longer and option, the availability is no longer in the user interface and there are no available methods to allow for it to be listed in the console as an option.
Configure a Scheduled Scan for a time outside of business hours or during the time in which Background Scanning was previously enabled. Please be aware, scheduled or manual scans can be resource intensive. This is the reason why it is suggested to configure the scan to run outside normal business hours or during non-peak usage.
Symantec Mail Security for Microsoft Exchange 7.0x or later.