I've found my launcher button is grey after every MA update since I switched my 'old' pc to that crap windows 10. It sticks at 95% on all updates.
I've found the solution is to launch the game window during MA working hours and for some reason the 95% updates to 100% and it works. I don't know why that is? Maybe there's some security feature MA switch on when they turn the office lights out.
Maybe that helps your issue.
Rick