FH3ArcFix

A small compatibility fix for Forza Horizon 3 (PC/UWP) failing to start on modern Intel Arc GPUs.

Status

v1.0.1 — confirmed working on multiple Intel Arc GPUs.

Primary test system:

• Forza Horizon 3 / Microsoft.OpusPG 1.0.125.2
• Intel Arc Pro B50
• Windows 11 24H2 (26100-series)

Also community-confirmed working on an Intel Arc B580 and Intel Arc 130T.

The game previously crashed shortly after launch with 0xc0000005 at forza_x64_release_final.exe + 0x1f28dec. With FH3ArcFix installed, the game launches and normal gameplay works on the tested machine.

Known issues:

• FH3 may still show FH204 — Unsupported graphics card detected. Choose Ignore and continue. FH204 suppression is intentionally not part of v1.0.x.
• Disable Frame Smoothing in FH3. On the tested Arc system, enabling it causes a severe performance drop.
• Minor pop-in or shadow/lighting flicker may occur. It is currently unclear whether this is Arc-specific or normal FH3 rendering behavior.

What it fixes

FH3 creates a null D3D12 depth-stencil view with DXGI_FORMAT_UNKNOWN. On the tested Arc system, the D3D12 runtime rejects this call, removes the device with DXGI_ERROR_INVALID_CALL, and FH3 enters its Video card fatal path.

FH3ArcFix proxies the system d3d12.dll and intercepts only that exact invalid call. It changes the null DSV format from DXGI_FORMAT_UNKNOWN to DXGI_FORMAT_D32_FLOAT. Every other D3D12 call passes through unchanged.

See docs/TECHNICAL.md for the implementation details, or docs/DEBUGGING_JOURNEY.md for the full investigation.

Install (binary release)

1. Download and extract the release ZIP.
2. Open PowerShell in the extracted folder.
3. Run:

powershell -ExecutionPolicy Bypass -File .\install.ps1

The installer finds the registered Microsoft.OpusPG package and places d3d12.dll in FH3's install directory.

FH3ArcFix does not require global Vulkan/DXVK variables, D3D debug settings, driver changes, or registry changes.

You can also manually place d3d12.dll in the Forza Horizon 3 game directory.

Uninstall

powershell -ExecutionPolicy Bypass -File .\uninstall.ps1

If you installed the DLL manually, removing the local d3d12.dll from the game directory also removes FH3ArcFix.

Build from source

The build scripts and source files are included in the GitHub source repository/source archive, not in the binary release ZIP.

Requirements:

• Visual Studio Build Tools with Desktop development with C++
• Windows SDK

From an x64 Native Tools Command Prompt:

build.cmd

Output:

build\d3d12.dll

For diagnostic OutputDebugString messages usable with DebugView:

build-debug.cmd

Safety / scope

• The standard release build enables the runtime patch automatically only for an adapter with Intel vendor ID 0x8086 whose name contains Arc.
• The experimental all-GPUs build removes that adapter restriction but keeps the exact same narrowly-scoped D3D12 workaround.
• The installer refuses untested FH3 package versions by default. Use -Force only if you are deliberately testing another build.
• The installer refuses to overwrite a different existing d3d12.dll unless -Force is used.
• No game files are distributed by this project.
• This project does not bypass Microsoft Store licensing or ownership checks.

Compatibility

Confirmed working on:

• Intel Arc Pro B50 — Windows 11 24H2, FH3 / Microsoft.OpusPG 1.0.125.2
• Intel Arc B580 — Windows 11 Pro 25H2 (community-confirmed)
• Intel Arc 130T — Windows 11 25H2 (community-confirmed)

Reports from other Arc GPUs are welcome.

For non-Arc hardware, use the experimental all-GPUs build described below.

Please include Windows build, driver version, FH3 package version, and exact GPU model when reporting results.

Experimental support for non-Arc GPUs

An experimental all-GPUs build is available for testing on D3D12 hardware that is not covered by the standard Intel Arc auto-detection.

This experimental variant removes the Intel Arc adapter check, but keeps the exact same narrowly-scoped workaround:

• only the confirmed null CreateDepthStencilView call is intercepted;
• DXGI_FORMAT_UNKNOWN is changed to DXGI_FORMAT_D32_FLOAT;
• all other D3D12 calls are forwarded unchanged.

Warning: The experimental build has not been validated on non-Arc GPUs. It is intended for testing and game-preservation work on older Intel GPUs, AMD/NVIDIA hardware, and less common GPUs such as Moore Threads and other alternative D3D12 implementations.

If you test the experimental build, please report:

• exact GPU model
• driver version
• Windows build
• FH3 package version
• whether the game launches successfully
• any crashes, visual artifacts, or performance issues

See EXPERIMENTAL_README.md for details.

Development

FH3ArcFix was developed using ChatGPT (OpenAI) through hands-on debugging on real hardware, including crash-dump analysis, WinDbg/D3D12 Debug Layer diagnostics, and iterative testing of the compatibility shim.

I wrote up the full investigation and how I worked with ChatGPT here: How I found the fix.

Disclaimer

Unofficial community compatibility project. Not affiliated with or endorsed by Microsoft, Playground Games, Turn 10 Studios, Intel, or OpenAI.

License

MIT. See LICENSE.