How to - Verify and Report WASM Crashes?

What is WASM?

The WebAssembly Module (WASM) is a container for running programmes written in other langauges (eg C/C++) that is then converted to native code ahead of time (as DLLs) during first launch (WASM Compilation). This helps improve performance for subsequent uses but causes longer load times on first launch. See for more info: 

 This also improves security of the sim and portability of projects across PC/Xbox/PS5. In case of issues, only the WASM crashes instead of the rest of the sim along side with it. This is why the sim and some functions may continue to work, however other systems and displays that use WASM on the aircraft become unresponsive or "freeze" in place. 

So what to do in case of WASM crash?

• Do not close the sim/restart flight immediately

• Verify the WASM error message & crash LVARs

• Report the WASM error message & crash LVARs with reproduction steps using the guide below.

Verify WASM Crash in Sim

Step 1. Enable Developer Mode 

FS24 Settings > General > Advanced Options 

FS20 Options > General Options > Developers

Step 2. Enable the Console by pressing "~" key on your keyboard or using the Dev Toolbar at the top of the screen

Step 3. Filter the Console by ❌Error messages only by clicking on ⚠️Warning and ℹ️Messages to disable them
(remove blue box border around them). 

Step 4. Type 'WASM' in the search box. Find the WASM Error and Copy the message. Also take a screenshot of this console window for making a report.

Step 5. Check the newly exposed INI_CRASH LVARs via the Behaviours Menu. Also take a screenshot of this for making a report.

Note: These variables will only be exposed after a WASM crash has been detected. These variables only record the last known state of various aircraft functions executed just before the crash was detected, not the source of it. This additional information is most useful during reproduction of the crash circumstances along with your autosave and reproduction steps requested below.

Report WASM Crash on Forum

Step 6. Paste the WASM Error message, screenshot of the Console and INI_CRASH LVARs obtained in Step 4 and Step 5 above into a forum post/discord message/ support ticket WASM Crash Report.

Step 7. Take note of what you pressed or things you did, just before you noticed this crash happen.

Step 8. Verify if you are able to repeat the crash by following those same steps.

Step 9. Please provide the following information

• Aircraft: A350-900 or -1000

• Simulator: FS2020 or 24

• Navdata Method: SIM DEFAULT or NAVIGRAPH

• OFP: Include a PDF of your Operational Flightplan (OFP) if related to FMS/Route Procedures crashes

• WASM Error: The error you copied in Step 4 above

• Specs: CPU, GPU and RAM of your system.

• Autosave File:  Please include the latest ".bin" autosave file prior to your crash. 

Step 10. Where possible, include on your report

• a Screenshot / Video showing what you pressed/did just before the crash happened to give us more clues. 

• steps on how to reproduce the crash so that we can try ourselves with debugging tools to identify the cause of crash.

• The Autosave File, include the latest ".bin" autosave file prior to your crash to help us reload into same scenario.
  
  

  Autosave Folder Paths

  FS24

  • Steam:
    %APPDATA%\Microsoft Flight Simulator 2024\WASM\MSFS2024\inibuilds-aircraft-a350\work\autosaves

  • MS Store:

    %LOCALAPPDATA%\Packages\Microsoft.Limitless_8wekyb3d8bbwe\LocalState\WASM\MSFS2024\inibuilds-aircraft-a350\work\autosaves

  
  FS20

  • Steam:

    %APPDATA%\Microsoft Flight Simulator\Packages\inibuilds-aircraft-a350\work\autosaves

  • MS Store:

    %LOCALAPPDATA%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\Packages\inibuilds-aircraft-a350\work\autosaves
    
    

  These types of WASM crashes are heavily dependent on the actions taken just before the issue occurs. Detailed reports of the exact steps leading up to the crash are extremely helpful, as if we’re able to reproduce the issue internally using the same sequence, our team can investigate, debug, and resolve it much more effectively.

Quote

Example WASM Crash Report

I had this WASM crash when I clicked the VIDEO button on the center pedestal.

To reproduce

• Load at gate

• Power on aircraft (Battery, GPU)

• Click VIDEO button

• Systems freeze 

Information

• Aircraft: A350-900

• Simulator: FS24

• Navdata Method: NAVIGRAPH

• OFP: Not required, happens on any route

• Specs: Ryzen 5800X, RTX 3070, 16GB RAM

• Autosave: Attached latest .BIN file before crash

• WASM: Error during MFD_gauge_draw execution. Error code : 0xc0000005