Hello @owwohlfarth, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/5285#issuecomment-3874115954.
proton experimentalx1 2026-020xc000001dx1 2026-02
Forza Horizon 5 crashes on Intel UHD 620 (i5‑8250U) during the loading screen after “Optimizing for your PC.” The game closes with no visible error. When running with PROTONLOG=1 and VKD3DDEBUG=1, the log shows repeated 0xC000001D EXCEPTIONILLEGALINSTRUCTION errors during DX12 pipeline creation. My CPU supports AVX, AVX2, FMA, BMI1, and BMI2, so this is not a missing‑instruction issue. The same hardware runs FH5 normally on Windows 11. Proton 8, Proton Experimental, Proton GE, and Wined3D all fail to launch the game. This appears to be a DX12→Vulkan translation issue specific to Intel UHD 620. I can attach full logs and vulkaninfo if needed. I am using Arch Linux with the newest Mesa and Vulkan drivers. I can attach full logs and vulkaninfo if needed.
Other Proton titles such as BeamNG.drive run normally on this system (including with Proton GE), so the issue appears to be specific to Forza Horizon 5’s DX12 pipeline on Intel UHD 620.