Not able to start after game service update

restart pc , also check that xbox app is up2date, if you start msfs with a “short link” then try to start directly / re-new the short-link.

See also topics like:

Where Start as admin is mentioned as workaround…

May be you find other hints:
https://forums.flightsimulator.com/search?q=access%20to%20the%20specified%20device%20path%20or%20file