Pkg.add error: "Unsatisfiable requirements" How to understand and attack these

Thanks everyone – especially for the suggestions about what was happening and troubleshooting alternatives.

To fix “the problem”,I just deleted Julia completely and started over fresh with 1.0.1.

But I learned more TRYING to fix it (by following the suggestions), so that was good.

I didn’t see or try dev command (thx @chakravala ) nor moving to another package environment (I don’t fully understand that one @y4lu though I sort of can guess and suppose I can check the documentation.

So the idea is to make a new directory, change to it, switch to package management, “activate” that directory as the package environment, check status (st) of Project.toml and status (st -m) of Manifest.toml

and of course thx again to @kristoffer.carlsson and over on slack @JeffreySarnoff