MU: Dark Epoch (3953520)

[fgguidi]

Compatibility Report

• Name of the game with compatibility issues: MU: Dark Epoch
• Steam AppID of the game: 3953520

System Information

• GPU: NVIDIA GeForce GTX 1070
• Video driver version: NVIDIA 580.173.02
• Kernel version: 6.8.0-137-generic
• Link to full system information report as Gist: [System Information](https://gist.github.com/fgguidi/600790be1a035bfab9364dbde548fe67)
• Proton version: Proton Experimental (experimental-11.0-20260805)

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

Symptoms

The MU: Dark Epoch launcher starts successfully under Proton, but shortly after opening it displays the following error:

Unhandled Promise Rejection
Error: Steam客户端未运行
at AppsflyerSteam.start (S:/steamapps/common/MU Dark Epoch/resources/app.asar/app/main/steam/appsflyer/index.js:1:14646)
at sendInstallInfo (S:/steamapps/common/MU Dark Epoch/resources/app.asar/app/main/sdk/index.js:1:219356)
at Object.oWLYn (S:/steamapps/common/MU Dark Epoch/resources/app.asar/app/main/sdk/index.js:1:56578)
at Object.pointUpload (S:/steamapps/common/MU Dark Epoch/resources/app.asar/app/main/sdk/index.js:1:63384)
at S:/steamapps/common/MU Dark Epoch/resources/app.asar/app/main/index.js:1:48606

Steam客户端未运行 translates approximately to:

Steam client is not running

However, Steam is running and the game was launched normally from the Steam client.

After dismissing the error, the MU: Dark Epoch launcher remains open. Pressing the START button does nothing and the actual game never launches.

Interestingly, the Proton log shows that the application's Steamworks integration is at least partially initialized.

The game loads its bundled steam_api64.dll from steamworks.js, as well as Proton's lsteamclient.dll and Steam's steamclient64.dll.

The log also reports:

[S_API] SteamAPI_Init(): Loaded 'C:\Program Files (x86)\Steam\steamclient64.dll' OK.

This happens despite the application subsequently reporting that the Steam client is not running.

The Proton log also contains an earlier:

RPC_S_SERVER_UNAVAILABLE

exception. I do not know whether this is related to the Steam detection failure.

Steam Support confirmed that MU: Dark Epoch is currently not supported with Steam Play and recommended reporting the compatibility problem to the Proton project.

Reproduction

1. Install MU: Dark Epoch through Steam on Linux.

2. Open the game's Properties -> Compatibility.

3. Enable Force the use of a specific Steam Play compatibility tool.

4. Select Proton Experimental.

5. Launch the game normally through Steam.

6. The MU: Dark Epoch launcher opens.

7. An Unhandled Promise Rejection dialog appears containing:

   Error: Steam客户端未运行
   

8. Dismiss the error.

9. Press START in the MU: Dark Epoch launcher.

10. Nothing happens and the game does not launch.

Expected behavior

The launcher should recognize the running Steam client and pressing START should launch the game.

Actual behavior

The launcher incorrectly reports that the Steam client is not running. After dismissing the error, pressing START has no effect.

Proton Log

Generated using:

PROTON_LOG=1 %command%

steam-3953520.log is attached below.

steam-3953520.log