Rolled Windows Update (Insider Preview) back to Build 17025. Problem has now gone away.
Possibly related to firewall filtering of outbound network connects (unproven). I will track windows forums and see if any likely direct cause turns up.
Armory does not try to connect to anything but localhost. Only Core creates sockets over the WAN.
fair enough, but windows seems to have changed processing in that area. Testing with just bitcoin core (0.14.x) that build of windows causes a prompt to allow / disallow external connection via firewall (with public / private network differentiation).
Bitcoin core by itself worked fine.
Shutting bitcoin core and starting armory does cause the same network / fireewall prompt to come up (you can see it in the taskbar on second screen) - but because the first screen is by then a Green Screen of Death, there is no way to confirm what it says).
Sorry - i've done no additional problem determination beyound that ... but hopefully it will be address (by MS) before the update is more widely released
