I have a Win10 guest in a VBox (5.2.32) on my kubuntu (18.04) host. It can not communicate with my USB scanner. I have installed the ext-pack and the guest-additions but Win10 still thinks there are no USB devices attached. I am using a USB mouse which Win10 can handle, but it can't detect my USB external drive or my USB scanner. WHat is confusing is that I had the same setup on an earlier computer (PowerSpec G313) which worked perfectly. I upgraded to a newer model (PowerSpec B742) which I set up the same way and now have that USB problem. I have spent an embarrassing amount of time trying to overcome this obstacle and am now in need of some advice.