I have Ubuntu 18.04 with Winows 7 Home Premium Service Pack 1 running in Virtualbox 5.2.32.
I have a USB thumb drive in one USB port and an ereader in another USB port. In Virtualbox if I click on 'Devices', point to USB and then click on 'USB Settings', the 'Enable USB Controller' and the 'USB 1.1 (OHCI) Controller' boxes are selected and the other 2 (USB 2.0 and USB 3.0) are not selected and all 4 options are grayed out. Under 'USB Settings' I can check the boxes for both USB devices and they will show up under the 'Devices and Printers' in the control panel under 'Unspecified' with a status of 'Device cannot start'. If I try to troubleshoot the devices Windows tries to find drivers for them but fails. Neither device shows up under Windows Explorer.
I have added my user ID to the vboxusers group and have installed the extension pack for Virtualbox 5.2.32. I have read several posts and answers to similar questions.
How do I get them to be available in Windows Explorer and, for the ereader, in Adobe Digital Editions?