R7000P Readyshare (again) USB device 'Cannot be stopped right now'

This is a recurring issue with several Netgear routers with Readyshare, and there have been several replies to this question, but none of them are actually helpful. For example, there are no suggested steps to find why the router thinks the device (in my situation, a simple, fairly modern, USB "thumb drive") can't be stopped, or how to make it stop.

On my LAN (hardwired Gigabit Ethernet), the workstation I use mostly is a fairly modern "desktop" with 64-bit Windows 10, patched current. From this workstation, until today, I have never been able to stop the thumb drive, even after re-booting both the router and Windows. HOWEVER, I just learned this: I chose to Sleep Windows (I could have chosen Shut down, of course), and used my old iPad mini via WiFi to choose [Safely Remove USB Device], it worked, and now I can remove and re-insert that same thumb drive, and on that same Windows box, choose [Safely Remove USB Device], and it works every time. Of course, in view of these observations, it could be that the Windows box has nothing to do with the issue.

Windows Media Player Network Service (WMPNetworkSvc) does not appear in the Everything tab of Sysinternals' Autoruns, and I don't normally use WMP, so I think that's not part of the problem, though of course who really knows, in Windows? Control Panel\All Control Panel Items\Network and Sharing Center\Media streaming options says, "Media streaming is not turned on", and it never has been, on this workstation, but of course this also may be irrelevant.

Bottom line: Can someone please document the cause of the actual issue, Readyshare USB "Cannot be stopped right now", and how to deal with it, for those unfortunate customers who have no alternate means of using [Safely Remove USB Device] on the affected Netgear routers?