Can I run a Fallout mod launcher and have Steam think it’s the original game executable?

Fallout 3 and Fallout: New Vegas have a great modding community, but most mods require launching the game through a mod manager like Fallout Mod Manager (FOMM), or by launching the Fallout Script Extender (FOSE), both of which exist independent of Steam.

I know I can ‘Add a non-steam game’ to my library (and in fact have been doing this for a while), but is there any way I can get Steam to launch FOMM or FOSE directly, by clicking the ‘Play’ button on the actual game?

This will enable me to use all my favourite mods, as well as continuing to utilise some of the Steam community benefits of launching the actual game.


You can actually rename the FOSE or FOMM launchers to ‘FalloutLauncher.exe’, which is the executable Steam looks for when launching the game. Steam will then launch the appropriate program, but still think that it is Fallout.

For example, I did these steps with FOSE:

  • Navigate to Fallout 3/New Vegas’s folder under steamapps.
  • Change the FalloutLauncher.exe file to be a different name, such as FalloutLauncher-orig.exe (in case you want to revert).
  • Create a copy of the fose-loader.exe file, and rename it to FalloutLauncher.exe (Leave the original named as fose_loader.exe, as FOMM will look for this file when you launch FOSE through it.)
  • Click Play in Steam. It should launch the game with FOSE.

I chose to do this with FOSE instead of FOMM, because FOSE launches the game directly. If I want to access FOMM, I still have it’s link as a ‘Non-Steam game’.

Source : Link , Question Author : Robotnik , Answer Author : Robotnik

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