It was as if the drive was completely invisible to Windows 10. I could hear that its power was on, but the drive did not appear in “This PC” and neither did it appear in the Device Manager. When I upgraded from Windows 8.1 to Windows 10, the external drive no longer worked.
Specifically, it is the Asus SBW-06D2x-U here: I have an external Blu-Ray/DVD external drive for my Windows laptop.