Scanning drives on the computer

Hello  and Welcome to the Webroot Community Forums!
 
Webroot only scans the files that are possible infection vectors (not all files on your system can deliver a malware payload) as there is no point scanning every file on your system.
 
Please Read:
Scanning for malware
http://www.webroot.com/En_US/SecureAnywhere/PC/WSA_PC_Help.htm#C2_Scanning/CH2a_RunningScan.htm
The difference between a 'deep' scan and a 'full' scan
https://community.webroot.com/t5/Webroot-SecureAnywhere-Complete/The-difference-between-a-deep-scan-and-a-full-scan/ta-p/6476

Thanks for the info.  Based on it,  the deep scan that runs as default is suffiicient.  In the article noting the difference between deep and full scans it states that the full scan would be useful on  USB drive that will be moved to another computer.  I do this occasionally for my job.  The instructions and data you referenced do not say how or if this can be done with Webroot.  At least I did not see it.  Am I correct in thinking I do not have an option to perform a full scan on a USB drive?  I don't see it as a problem, just wanted to know if it could be done.