Hi, what seemed to make it work for me was updating to the current version 2004 of Windows 10 and the Microsoft rep I was working with also talked me through resetting the app itself. Go to all apps using the windows button, right click on the microsoft flight simulator app, then more-settings, then a new window will open. Scroll down and hit the Reset/reset button.
I am not sure which item corrected it for me, or if it was a combination of both as the windows update and the app reset actions were completed at the same time. I also had to reboot my computer a couple of times because it seemed like it was frozen after restarting the app where the insert disk message did not appear. It then went into a download screen for 95 Gb which took me about 3 hours to download and install. It seems to be working now but I don't know how to do anything yet because I haven't hooked up any of my flight items e.g. joystick, yoke.
Good Luck.