I am an Avast Free user. Does this protect /scan any USB or portable drives I may access via my desktop? Also how simple is it to use? We have a number of desktops running in my environment on this version of Avast. Please comment and make any recommendations. Thank You.
Does this protect /scan any USB or portable drives I may access via my desktop?Yes >>> https://blog.avast.com/2012/09/27/how-do-i-scan-a-flash-drive-for-viruses-using-avast/
Also how simple is it to use?If you have installed it you should know ....
No security program have 100% detection or zero false positives
Recomended USB protection tool: MCShield >> http://www.mcshield.net/
It is free, install and forget … surf that website for info
This is not a antivirus but a special tool designed to target those malwaretypes that jump disk
By default, it will scan anything you open or access on a flash drive, Memory card or external HD.
If you expect more than that, you need to change the settings.
(Reporting Pondus because you didn’t like his answer isn’t going to change the answer even if it isn’t what you wanted to hear.)
Further review has determined the Free version does not automatically scan all items opened from a flash drive, a target scan must be run manually.
If you plug in a full 256GB USB stick (or larger) do you want it to auto scan all that evry time?
Any file you open / read / move / save … is scanned by realtime protection
That isn’t entirely correct.
Only files that are likely to be a threat if infected would be scanned. e.g. text files for instance. Others might include zip/archive files, certain image files, etc. This would be pretty much be the default settings (or any customisations) in the File System Shield.
If you open a compressed file, it will be scanned before you have access.
You’re correct that by default, that file type isn’t scanned by Avast when you first connect that USB drive.
Thanks
You’re welcome. Follow the advice Pondus offered and install McShield.
It will check for the part your AV doesn’t check by default and then your AV takes over for anything you open on that drive.
(Layered Protection)
What I offered in the other thread! That’s not fair.
:-X
Many of us have recommended it going all the way back to 2013. 
I see.
BTW: Last year, I bought a USB drive (64 GB) and tried to use it under XP. But that old os only meant, it
should be formatted! So: Too much is too much …