Monterey not showing my external Samsung T5 drives

Hello, sgvogel.

Sorry that you're having this trouble.

Since the upgrade have you confirmed that the external drives are enabled to show on the desktop and in the Finder sidebar?

Navigate to Finder > Preferences > General tab and Sidebar tab.

Are the drives connected directly to the Mac rather than to a hub or dock?

If rebooting your Mac doesn’t fix things, see if the problem still happens in Safe mode (hold the shift key down at startup). It can take much longer to safe boot (10 min) so be patient.

How to use safe mode on your Mac - Apple Support 

Safe mode disables loading third-party drivers, forces the OS to clear certain caches and logs and does other miscellaneous housekeeping. It's non-destructive to user data so is safe to do. Very often certain weird software behavior is corrected by simply logging in this way as a troubleshooting method. When you're in safe boot, the machine will not be at its best performance, especially with graphics, but that's expected.

Does the problem persist while in Safe mode?

Exit safe mode by restarting your Mac normally and re-evaluate the issue again.

It is not up to Apple to ensure third party peripherals work, it is us to the developers of the peripheral manufacturers, that is why Apple and all manufacturers offer beta programs. To test and de-bug.

I would say restart in Safe Mode ( Use Safe Mode to isolate issues with your Mac ) with the Samsungs and any other external peripherals disconnected from the Mac (unplug all cables and power down the peripherals) then after you have restarted normally beginning introducing each external peripheral, test then add the next and rinse and repeat until done. If the problem continues, you need contact Samsung for support to see if they are already aware of the problem.

You're welcome.

Thank you for the update. I agree with @rkaufmann87 that it's odd they show up on the dtop but not in Finder.

To add, for clarity, one would't expect these external drives to appear among the listed files and folders within the Finder window for the Desktop folder. Of course, they may be visible in the sidebar of any Finder window.

You have enabled "External drives" to be visible via Finder's Sidebar Preferences, yes?

Well, regardless, it's good that access has been restored.

Take care, friend.

Odd they don't show up in Finder but are showing on your desktop but I'm glad you were able to locate them again.