The first thing to diagnose: is this an issue with the drive or with the PC? So find another PC or laptop and try there. And, to be sure, get another hard drive to try on this PC.
My guess: the drive is defective. Then the next step: get the hard disk out and put it in another enclosure. If it works now, it's solved. If it doesn't work now either, buy another external and consider all files on your current drive that you didn't backup, as lost.
Some people don't backup, because they don't care about the particular data on the disk; some people forget to backup important data. Let's hope you're not one of those.
Windows 10 can no longer access my external hard drive. WD Book 2 TB. Started after I tried to upload a video to an online website. Received an error message on that website. I have run Norton anti-virus full scan twice and nothing was found. I have used Data Lifeguard to check the functioning of the Ext drive itself. If I unplug the hard drive from the computer, when I click on the Files/My computer icon, I can easily access all the program files, downloads, etc. When the hard drive is plugged into the computer, when I click on the icon, the window pops up listing everything connected to my computer, files, downloads, etc, including the Ext. Drive. However, I am unable to interact with anything in that window and after a few moments, my wallpaper image goes black, the pop up window goes away, then the wallpaper image comes back. If I click on the icon a second time I get the blue wheel (I'm working) for a moment, then the window closes again.
Any suggestions on what's wrong and how to access my hard drive?