Steam – How to force Steam to run a post installation script again

steam

Steam has a couple of scripts that are executed after the installation of a Game or Program. They say what else needs to be installed or what registry keys need to be created. Some examples:

  • Just Dance 2017 installs Uplay, declared in "steamapps\common\Just Dance 2017\Support\Installerscript.vdf"
  • GTA IV creates "HKEY_LOCAL_MACHINE\SOFTWARE\Rockstar Games\Grand Theft Auto IV", declared in "steamapps\common\Grand Theft Auto IV\GTAIV\installscript.vdf"

Is there a way to force Steam to run the post installation scripts again?

Best Answer

From https://partner.steamgames.com/doc/sdk/installscripts :

The install script is marked in the depot manifest. You can see this in the generated manifest.txt file as a 100 in the Flags field.

When a Steam user is starting a game, Steam will scan all of the mounted depots for that game for any file with the install script flag and run them.

From what I understand, you need to find that manifest.txt file for specific game and update this Flags field back to initial value (100).

This answer suggests that for each dependency Steam may actually create a registry entry, which means it may be required to clean the registry before trying to relaunch install scripts.

And it also works only for Windows:

NOTE: Install script functionality described below is primarily for Windows operating systems. MacOS support is limited to file permissions and symlinks. There is no Linux/SteamOS install script functionality at this time.

Unfortunately, I don't have Windows machine right now and cannot validate this.

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