It seems you have set some "Compatibility" setting either for the sim or for Couatl.exe. Sometimes, Windows can automatically sets those compatibility flags without your intervention.
Try running the FSDT Live Update now, because when it's running, if will clear those wrong compatibility settings from the sim .exe, and be sure you haven't set any compatibility setting for Couatl.exe too, perhaps trying to fix a problem we never had in the first place.