Not able to mount any usb drives after upgrading to sur

[colourfastt]

I just tried plugging in my TM backup external drive and it did not appear on the desktop.
I got this displayed
View attachment 1672402
I put in the password and after a few seconds it appeared on my desktop.

This is really obvious but the external drives option is ticked to show on the desktop in your Finder preferences isn't it?
In my fresh install it wasn't ticked.

Always has been, but I double-checked and, yes, it's ticked.

 

[RussellLaPLante]

I had a slightly different USB storage device not mounting, or appeared to not mount. As a creature of habit I would always to the Finder>Locations to copy photos from my Flir C3 camera. That was the easiest location. After the Big Sur update it stopped being listed. For a few weeks I resorted to using my 2012 MacBook Pro that does not support Big Sur to transfer and sneakerNet the images to my iMac.

Then I happened to notice the device was in fact being displayed on my desktop. I just had not noticed (clutter and all) It worked fine but still not listed in the under "Locations" in Finder my goto.

It always displayed as "Untitled." On a whim today, I renamed it from Untitled to FlirC3, ejected it and reattached it. Low and behold FlirC3 is now listed in Locations. There must have been a change, likely security related that does not allow "Untitled" devises to be listed in Locations