It's been a while, but one update of NX-D messed up for me on Win 10, and did more or less the same thing, and I was able to fix it by installing it from an administrator account. If, like most people, you are our own administrator, your regular account includes most but not all of the characteristics of a full administrator account, but the differences are not made clear. If you're a Win 10 guru you could probably figure out what they are and tweak the permissions and whatnot, but the easiest thing I found to do was to go to the dashboard and set up an administrator account. When I log on, the menus and whatnot are different, and when I reinstalled NX-D from that account, it worked again. Subsequent updates haven't had the same problem but it's a handy thing to have that account there anyway.