onlinefix_heroic.md

Quick Guide: Running OnlineFix Games on Linux via Heroic Launcher

This guide provides a universal template for running sideloaded OnlineFix multiplayer games in Heroic Games Launcher using GE-Proton, while preserving Steam integration and multiplayer functionality.

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Step 1: One-Time SpaceWar Setup

Before configuring any game in Heroic, initialize a working SpaceWar (AppID 480) environment.

1. Install SpaceWar

Make sure the native Linux Steam client is running, then execute:

steam steam://install/480

2. Enable Proton

In Steam:

1. Open Library → SpaceWar → Properties
2. Navigate to Compatibility
3. Enable Force the use of a specific Steam Play compatibility tool
4. Select your preferred GE-Proton version

3. Initialize the Prefix

1. Launch SpaceWar once from Steam
2. Wait for it to start
3. Close the game

This creates the required Wine prefix that Heroic will later reuse.

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Step 2: Configure the Game in Heroic

Add the Game

1. Add the game as a Sideloaded Game in Heroic.
2. Set the executable path to the game's actual executable.

Important: For Unreal Engine games, the correct executable is often located inside:

GameFolder/Binaries/Win64/

rather than in the root game directory.

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1. Redirect the Wine Prefix

To avoid Error 126 (failed to load steamclient), point Heroic to Steam's initialized SpaceWar prefix.

Wine Prefix:

/home/<username>/.local/share/Steam/steamapps/compatdata/480

Example:

/home/m/.local/share/Steam/steamapps/compatdata/480

Replace <username> with your Linux username.

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2. Configure Proton & Runtime

Setting	Value
Wine Version	GE-Proton (latest recommended)
Use Steam Runtime	ON

Why?

• GE-Proton provides the compatibility layer.
• Steam Runtime allows UMU to bridge Heroic with the running Steam client.

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3. Add Environment Variables

In Heroic → Game Settings → Environment Variables, add:

Key	Value
WINEDLLOVERRIDES	OnlineFix64=n;SteamOverlay64=n;winmm=n,b;dnet=n;steam_api64=n;winhttp=n,b
GAMEID	480
UMU_ID	480

Purpose

Variable	Purpose
WINEDLLOVERRIDES	Forces Wine to load OnlineFix DLLs instead of native ones.
GAMEID=480	Makes the game identify as SpaceWar.
UMU_ID=480	Allows the container to connect to Steam's communication socket.

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Step 3: Play

1. Ensure the Steam client is running in the background.
2. Launch the game from Heroic.
3. Steam should display:

Playing SpaceWar

You can now use Steam invites and multiplayer functionality.

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Troubleshooting

Error 126 / Failed to Load Steamclient

Possible causes:

• Steam is not running.
• Wine Prefix path is incorrect.
• SpaceWar was never launched to initialize its prefix.

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Game Crashes Immediately

Verify that Heroic points to the game's actual executable.

Common example:

GameName-Win64-Shipping.exe

Avoid launchers or shortcut executables.

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Black Screen / No Launch

Check that:

• OnlineFix.ini exists in the game directory.
• The file is not corrupted or missing.
• Required OnlineFix files were extracted correctly.