Since updating from Win7Pro to Win10pro, I cannot install any new fonts. I can view fonts already installed and the ones I am trying to install, but when I try to install a new font, a window flashes briefly and goes away. No error message.

I've tried:

right-click install
right-click install as shortcut
drag to Control Panel\All Control Panel Items\Fonts
I've double clicked and can preview - Install button visible and clicked install
drag to windows\fonts folder

All produce same result - momentary window and font not installing.

I was able to capture part of the window with a screen shot. Took several tries because it disappears so quickly.
Click image for larger version. 

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UAC is set to Notify only when Apps...
Firewall is on
Tried with AV on and off.
Tried with Firewall off

Tried multiple different fonts, both new and already installed ones.