On Macintosh systems, removable volumes such as USB drives, CD/DVDs, etc. are referred to by Symantec Endpoint Protection as "mounted disks". SEP AP (Symantec Endpoint Protection Auto-Protect) includes configurable scan preferences for such volumes.
The behavior of such "mount scans" has changed between SEP versions, and its impact on SEP performance is not always clear.
SEP "Mount Scans" may interfere with Mac OS X performance.
The following points and considerations may be observed for SEP Macintosh "Mounted Disk" scans.
Mac OS X
Symantec Endpoint Protection 12.1