Win 10: Difficulty Ejecting External Hard Drive

System: Windows 10 Home 909 (build 18363.1082)
Laptop: HP 17-by1xxx

Laptop has USB 3.0 ports. My external hard drives are USB 2.0. I plug the external drive into the laptop, open Windows Exporer to look at one file on the external hard drive, then exit from Windows Explorer. When I click on the icon to eject the external hard drive, I receive a warning message that the drive cannot be ejected because there is an application using it. But I had closed Windows Explorer so there should be no other app using the external drive. Right?
The only way I can "safely" eject the hard drive is to reboot the laptop. I tried signing out then signing back into the account, but when I try to eject the hard drive, I receive the same warning message.

Am I missing something?
What can I do to eject the external hard drive without rebooting?
Can I safely unplug the external drive without going through the Win 10 eject process?

 

I've had to live with this same problem for years, never found an answer, but I just put the laptop to sleep rather than rebooting.

 

This is an old problem.
Read this.
https://appuals.com/fix-cant-eject-external-hard-drive-on-windows-10/

You can also try this.
https://m.majorgeeks.com/files/details/usb_safely_remove.html