Having an epiphany this morning, after a third cup of coffee with the grounds at the bottom (the stiff stuff). I thought what if I try running LyX in administrator mode?
I switched back to the Win 10 Enterprise with my UW thesis because ultimately that is what I need to get working. I did try rolling back to 5 various versions on the thesis using git and this failed for every previous version I tried... versions I am certain worked on the version of LyX and MikTeX that have not changed on the machine. Then I ran LyX in administrator mode and compiled exact version that previously failed and it worked (with errors as typical) and showed the dialog with "Show Output Anyway" which once clicked as before now shows the pdf again. I think there is a very real problem on Win 10 Pro, Win 10 Enterprise of permissions between LyX and MikTeX. But hey at least as administrator I can get my Thesis to be generated. Any thoughts by Devs on if this is a real problem knowing that us users can't be believed?