In my Avast free version, I have it set to auto scan when a Usb flash drive is attached but when I attach one, no scan is initiated. I thought maybe it was scanning in the background but there is nothing under scan logs or history scans. Sure I can always manually scan by right clicking the drive but isn’t it better to have Avast autoscan when inserted as an enhanced preventive measure? Does anyone have any advice on this?
avast! scans your USB devices when there is something which trying to execute suddenly just after you attached it (mostly a threat). Else it doesn’t matter, avast! will check while you trying to execute files on it and take preventive actions real-time. if you wanna check whole lot of stuff in your USB drive just after attached it, then it will make your system busy and most users may not agree. That’s why they offer manual scan if you need to have it first. So with avast! don’t be worry, you are safe.
I feel the same.
Kaspersky, although, shows a popup asking the user to scan the whole USB or not. You can also set one action as the default.
Yeah, that’s true. Although Kaspersky pop-up is annoying when each time attach an USB device. avast! real-time scan make you safe, don’t bother if your definitions already up-to-date 
Cheers…
Choose to remember your choice and the popup won’t come back
Yeah, I mean if avast setup a pop-up like that it would be annoying. Anyway I’m not a Kasperky user. Thnx
Cheers…