Portable external drive no longer shows on my desktop

A portable external HDD - a Western Digital 1TB MyPassport - no longer shows in This PC and File Explorer on my desktop. The device does show in Device Manager. It also shows in This PC and File Explorer on a laptop (also running Win 10 1909). The PC maintenance is up to date except for this week's KB4497165. Both the PC and laptop show the same driver for the drive - a generic MS driver 10.0.18362.1 dated 6/21/2006.

I don't remember exactly when the drive last worked on the PC - maybe up to 6 months ago. I use it on my laptops much more than on the desktop. But I'd like to use it on the PC right now and I can't. Any idea what I can do to get this to work?

Oh. Yes, I've rebooted. Yes, I've tried multiple USB ports (although Device Manager sees the drive regardless of the port I use).

pokeefe0001 said:

A portable external HDD - a Western Digital 1TB MyPassport - no longer shows in This PC and File Explorer on my desktop. The device does show in Device Manager. It also shows in This PC and File Explorer on a laptop (also running Win 10 1909).

If it shows in the laptop it sounds like there isn't a fault with the drive. Can you explore it and see files and folders when on the laptop? If so it seems to be OK.

Open Disk Management. If it shows the drive and its partition says 'Healthy' but the partition has no drive letter, then right-click on its partition and select 'Change drive letter and paths...'. Give it a drive letter and it should then appear in This PC and File Explorer.

I was able to explore the drive with no trouble on the laptop so I went into Disk Management, as you suggested, found the device, assigned a drive letter, and now all is better.

So thank you.

Now, any idea why I had to do that? Why would Windows not assign the drive letter automatically when I attached the device? It did that in the past, and it was doing it for USB flash memory sticks today.

pokeefe0001 said:

I was able to explore the drive with no trouble on the laptop so I went into Disk Management, as you suggested, found the device, assigned a drive letter, and now all is better.
So thank you.

Now, any idea why I had to do that? Why would Windows not assign the drive letter automatically when I attached the device?

By default it should automatically assign a drive letter to any new drive when you plug it in, USB or HDD. But automount can be turned off and occasionally seems to have got turned of for no obvious reason. This tutorial tells you how to turn it on.

Enable or Disable Automount of New Disks and Drives in Windows

Yup, Automount was disabled.

I had recently tested a program that scans and optionally updates drivers. No reason to assume it would do anything to Automount, but I generally distrust programs supposedly automate maintenance so I'm willing to blame it.