I have the same issue.
Really I have several Win 10 installation, one of them remain at b9926 and there i managed to install a different driver (350.12) from the recent one; in that installation I have no problem with Q400 or any other sw around FSX.
In my experience the problem started with b10042 and still remain on b10130.
I have an nVidia 460GTX with 768MB of VRAM coupled with MS installed driver which is 347.25.
Would be usefull to know which grafical card & driver have you.
Andrea