Here is a situation that can be really confusing. You plug in your flash drive and open File Explorer and don’t see any drives. One solution is to go to File Explorer, View, Options, and select the dropdown in the General tab and change it from “Quick Access” to “This PC” and hit Apply. You will need to close File Explorer and reopen it to see the changes. Now you will be able to see your drives, including the flash drive you plugged in. Hope this helps!