External hard drives scanned during Full System Scans?

I have an external hard drive hooked up to my computer via a USB drive. Will Norton 360 automatically scan the files on this external drive during a fall system scan?

 

Part of the reason I'm asking is I'm noticing that this scan has scanned over 500,000 files, more than I ever remember being scanned before. So I thought maybe it's scanning the external drive also, which would add to the number of files to be scanned.

 

Best, David