WARDOGS Playtest (4809930)

WARDOGS Playtest (4809930) – Elytra InstallModule fails opening CAB through Volume GUID path
Compatibility Report

Name: WARDOGS Playtest
Steam AppID: 4809930
Distribution: Linux Mint
Kernel: 7.0.0-28-generic

Proton versions tested

The issue reproduces with:

Proton Experimental
Proton 11.0-2
Proton 10.0-4

A completely fresh Proton prefix was also tested.

Symptoms

WARDOGS starts the Elytra anti-cheat/service installation, but Elytra fails during InstallModule.

The Elytra error dialog reports:

InstallModule failed

RPC error:
Failed to open input file

crates/bin/service/src/server_module.rs:28

File not found. (os error 2)

The module identifier involved is:

042074521588d69599a364e2f975460e68551832d35317ce19bd30af43e9cca90758
Investigation

Testing with:

PROTON_LOG=1 WINEDEBUG=+file %command%

shows that Elytra successfully creates/downloads:

C:\users\steamuser\AppData\Local\Temp
042074521588d69599a364e2f975460e68551832d35317ce19bd30af43e9cca90758.cab.part

It then renames it to:

C:\users\steamuser\AppData\Local\Temp
042074521588d69599a364e2f975460e68551832d35317ce19bd30af43e9cca90758.cab

The CAB exists and can be accessed through the normal C: path.

However, Elytra subsequently attempts to open the same CAB using a Windows Volume GUID path:

\?\Volume{00000000-0000-0000-0000-000000000043}
users\steamuser\AppData\Local\Temp
042074521588d69599a364e2f975460e68551832d35317ce19bd30af43e9cca90758.cab

Wine then fails the file open with:

CreateFileW Unable to create file ... (status c0000034)

After the failure, the downloaded CAB is removed.

MountedDevices

The Proton prefix contains:

HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

??\Volume{00000000-0000-0000-0000-000000000043}
REG_BINARY 2E2E2F64726976655F6300

\DosDevices\C:
REG_BINARY 2E2E2F64726976655F6300

Therefore the Volume GUID used by Elytra and C: appear to reference the same backing path.

Nevertheless, opening the CAB through the Volume GUID path fails while the regular C: path works.

Reproduction
Install WARDOGS Playtest (Steam AppID 4809930).
Force Proton Experimental, Proton 11.0-2, or Proton 10.0-4.
Use a fresh compatibility prefix.
Launch the game.
Elytra installs and starts its service.
Elytra downloads the module CAB to %LOCALAPPDATA%\Temp.
Elytra attempts to access the CAB through \?\Volume{...}.
CreateFileW fails with status c0000034.
Elytra reports InstallModule failed / Failed to open input file / os error 2.
Expected result

The Volume GUID path corresponding to the Proton C: drive should resolve to the same file as the normal C:... path, allowing Elytra to install its module.

Actual result

The CAB can be downloaded and accessed through C:..., but opening the same file through the corresponding \?\Volume{GUID}... path fails.

The behavior is reproducible after deleting the entire Proton compatibility prefix and allowing Steam/Proton to recreate it.

Reproduce with WARDOGS Playtest (Steam AppID 4809930) on a fresh prefix using Proton Experimental, Proton 11.0-2, or Proton 10.0-4. Start with PROTON_LOG=1 WINEDEBUG=+file and inspect the MountedDevices mappings and the failing Volume GUID path in the file trace. Done means the CAB in %LOCALAPPDATA%\Temp opens through the corresponding Volume GUID path and Elytra completes installation.