Microsoft Flight Simulator FAQ

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WASM Support FAQ


Current Known Issues:

1. On Xbox, if Microsoft Flight Simulator: Add-on Support is installed/updated when the game is launched, the below WASM supported Marketplace content may initially not function correctly if it was previously installed. See: for workarounds.


What is WASM on Xbox?

WASM is an acronym for WebAssembly Module, and Microsoft Flight Simulator uses WebAssembly for scripting. On Xbox, the “WASM module” is contained in a separate Xbox add-on (Microsoft Flight Simulator: Add-on Support). This add-on is automatically installed when Microsoft Flight Simulator is launched on an Xbox Series X|S console or Xbox Game Streaming (xCloud). The PC Windows Store/Steam versions of Microsoft Flight Simulator do not require this add-on.

What does WASM on Xbox do?  

By installing Microsoft Flight Simulator: Add-on Support, certain features (within Marketplace content) become functional or begin functioning as intended. Most commonly this means aircraft instruments, such as controls, panels, and displays, will function as intended (without WASM these instruments may not function at all or would function incorrectly). However, WASM usage is not only limited to aircraft.

Where do I get WASM on Xbox?

On an Xbox Series X|S console, the WASM add-on will automatically install in the background when you launch the game. On Xbox Game Streaming, the add-on will be installed on the server before the session is initiated. There is no need to search for/install Microsoft Flight Simulator: Add-on Support from the Xbox Store.

On an Xbox Series X|S console, you may notice weekly updates to Microsoft Flight Simulator: Add-on Support in the background or when the game is launched. These weekly updates are updating WASM functionality for Marketplace content, and not limited to only the Marketplace content you own.

How do I check which version of WASM is installed?


NOTE: This will only work on an Xbox Series X|S console (not on Xbox Cloud Gaming/xCloud).


When reporting an issue with WASM on Xbox, it may be necessary to check which version of the Microsoft Flight Simulator: Add-on Support is installed:

  1. On your Xbox Series X|S console, launch My games & apps.
  2. Navigate to Games, and place the cursor over Microsoft Flight Simulator.
  3. Press the menu button (three lines) on the controller, and select Manage game and add-ons from the context menu.
  4. Within the context menu, press the menu button on the Microsoft Flight Simulator tile and select “Manage installation …”
  5. Navigate to the Downloadable add-ons area and press X on “Microsoft Flight Simulator Add-on Support”msfs1.png
  6. After pressing X, the version number will be displayed in the FullName at the top of the UI (ex.

What can I do if WASM isn’t working?

If you encounter a WASM issue in-game, you may see an error that begins with “You are missing additional content and may encounter unexpected behavior.” This can also occur if you purchase Marketplace content supported by WASM but do not have the most recent version of Microsoft Flight Simulator: Add-on Support.


Should you encounter this error, please do the following:

On Xbox Series X|S

  1. Close and relaunch Microsoft Flight Simulator.
  2. If this does not work, restart your Xbox Series X|S console (hold down the Xbox button on the controller and select “Restart console” from the power menu), then relaunch Microsoft Flight Simulator.
  3. If the issue persists following a console restart, submit a ticket.msfs4.png

On Xbox Cloud Gaming (xCloud)

  1. Submit a ticket.  
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