Hi,
If you navigate to the following drive: C:\ProgrammeFiles\WindowsApps there should be a folder called "Microsoft.FlightSimulator_1.16.2.0_X64_8WEK.....". Right click on this folder and select "Properties". In the new window select the "Security" tab and select "Edit" to edit the permissions. From there you should be able to highlight the Administrator account and add Full Control permissions to the folder for Admin.
Please note the above path is where it installed from MSStore purchase. I am not sure if the path is the same for STEAM?
Hope that helps
Rich