Steam - How to Repair or Uninstall Microsoft Flight Simulator

HOW TO REPAIR THE INSTALLATION - VERIFY INTEGRITY OF GAME FILES 

1. Launch Steam
2. From the Library section, right-click on Microsoft Flight Simulator and select Properties
3. Select the Local files tab then click the Verify integrity of game files... button.

4. Steam will scan the installation and download missing files or remove outdated or corrupted files - this process may take several minutes. 

Warning: By default, the launcher and the Core Content Packages are installed at the following location.

C:\Program Files (x86)\Steam\steamapps\common\MicrosoftFlightSimulator

If during the Packages installation process you have selected the following folder as the Packages Installation folder:

C:\Program Files (x86)\Steam\steamapps\common\MicrosoftFlightSimulator\Packages

The Packages will be wiped out and you will need to redownload the Packages the next time you launch Microsoft Flight Simulator. See also: Why am I redownloading all the packages after each update?

HOW TO UNINSTALL MICROSOFT FLIGHT SIMULATOR

1. Right-click on Microsoft Flight Simulator then select Manage and click on Uninstall Game
   
2. Click on Uninstall to confirm your choice

Warning: Once uninstalled, make sure that all the packages (including Community packages) are deleted. The default package installation location is:

C:\Users\YourUsername\AppData\Roaming\Microsoft Flight Simulator\Packages

If you have installed the packages in a custom folder, search for that folder instead. Move any leftover files or folders to the Recycle Bin.

DO A CLEAN INSTALL OF MICROSOFT FLIGHT SIMULATOR

To reinstall the sim, open your Steam library, search for Microsoft Flight Simulator and click "Install"