So, I tried using a Virtual Machine, or VM, directly on my Mac. While that worked well for the most part, the primary issue ...

You may get VirtualBox failed to open/create the internal network when you start a VM on Windows. The suggestions in this post are sure to help you.

From Googling, it seems to be a VMWare-only thing? One guest is VMWare, the other is VirtualBox. I don't think I've changed any setting or physical connection, but clearly something is different ...