Checklist Proton bugs

This is a checklist to help you find relevant error messages in your Proton log.

General guidance

Search the Proton log for the following prefixes to find errors/warnings:

• fixme:
• err:
• warn:
• error:

---

Game won't start at all:

Steam2.dll

Tracked at https://github.com/ValveSoftware/Proton/issues/2613

• warn:module:load_builtin_dll cannot open .so lib for builtin L"Steam2.dll":

Valve CEG DRM

Currently Steam for Linux does not generate the custom executable for games using Valve's CEG DRM, this is tracked at https://github.com/ValveSoftware/Proton/issues/753

You can look for cegpublickey on https://steamdb.info/app/<appid>/config/ to check if a game is using this.

---

Missing cinematic/cutscenes:

Problems with missing cinematics/cutscenes are most likely due to Media Foundation, Quartz or WMVcore issues. These are tracked at https://github.com/ValveSoftware/Proton/issues/1464

Media Foundation

• mfplat.dll
• mfplay.dll
• mfreadwrite.dll
• mfstartup.dll

Quartz

• quartz.dll
• fixme:quartz:MPEGSplitter_QueryInterface
• err:quartz:GetClassMediaFile Media class not found

WMVcore

• WMVcore.dll
• fixme:wmvcore:WMReader_Open
• fixme:wmvcore:WMCreateSyncReader

XNA

• Microsoft.Xna.Framework.Video.dll

---

Audio playback issues:

Xaudio2

Xaudio2 issues are labeled "XAudio2" by the moderator. The Proton log typically includes one of the following:

• XAudio2_7.dll
• xaudio2_8.dll

---

Other errors:

.net

.net issues are labeled appropriately by the moderator. These include:

• .NET-UE3 (Unreal Engine 3.)
• .NET-winforms (System.Windows.forms toolkit)
• .NET-WPF (PresentationFramework)
• .NET-XNA (Uses XNA framework, implies Xaudio2 and possibly WMP)

---