So, just as I was about to lose my will to live, I watched a video and found the solution.
In the properties for the folder, security, advanced, EFFECTIVE ACCESS the user "everyone" was listed twice. One instance prohibited folder access. I deleted that "everyone", I think in permissions?
Magically, it now works. Considering that NOBODY has access to my machines, how does that **** happen?
Rhetorical question. It's Windows.