WetGeek Still, I continued with it.
And I didn't get any farther with Elementary than I did with Ultramarine. I needed to connect to my email account in order to fetch a message I sent myself a while ago containing text to use to modify /etc/fstab, and my list of .bashrc additions. I tried using Elementary's Mail app, but could not.
In the online accounts (system settings) I provided it with the same information I use to connect to my email account everyhere, but the Mail app couldn't connect. So I used apt to install Thunderbird, gave it exactly the same settings, and connected immediately.
After modifying /etc/fstab and mounting all the shares, I still couldn't get Files to access the shares. This time I realized that I'd been using the terminal as root when I accessed the shares in the terminal. I exited back to my user, jerry, and was unable to access them.
So I changed to root again and saw a listing several pages long. Here are a few examples from that list:
Notice the owner in those lines. I'm not sure who 1026 is, but I'm pretty certain it isn't me. And with an owner like that, it's no wonder that Files won't allow me access. Since other VMs I've created don't have this problem, I'm going to check one of those and see what's reported for these files.
...
Here's an example of the same share as mounted in my Solus Budgie VM.
Hmm ... I'm shocked. Apparently I AM 1026. I've always thought I should be 1000, being the only user in the system. Apparently what I've always believed was not correct. But that still leaves an important question in my mind, "how is it, if I really am user ID 1026, that I cannot access 1026's files in the Files utility"? It should be user 1026 that's logged on and using Files, no?
Here's how it works in Solus Budgie (and lots of other VMs):
I still don't know what's the root cause of this problem, but apparently it's not the distribution, since Ultramarine is based on Fedora and Elementary is based on Ubuntu. They have the same DE (in this case), but it's hard for me to understand how the DE could affect file access rights. Still, Ultramarine Budgie was perfectly happy to give me access to these same shares, and Ultramarine Pantheon was not. The difference would seem to be the DE, whethe I find that easy to believe or not.
In the end, I'll just consider this a problem I couldn't solve, and move on. It's time to take a look at Serpent OS now.