protonscr

Rallysimfans Richard Burns Rally - Proton 11 regression with detecting .NET runtime

protonclosed
ValveSoftware/Proton#10149 · opened 2026-09-16 by immyj-trv · updated 2026-09-16 · 3 comments · github
Iimmyj-trv 2026-09-16 github

Compatibility Report

  • Name of the game with compatibility issues: Rallysimfans Richard Burns Rally
    Not a steam game, this seems more like a general Proton issue.

System Information

  • GPU: 9070 XT
  • Video driver version: Mesa 26.1.8
  • Kernel version: Linux 7.2.5-200.fc44.x86_64
  • Link to full system information report as Gist:
  • Proton version: 11, experimental, anything newer than Proton 10, including community forks

I confirm:

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

steam-15719751810027618304.log

Symptoms

Game launcher requires .NET 10.0.9 Desktop runtime installed, both x86 and x64. The runtime is installed and recognized by Proton 10, specifically GE Proton 10-34 but same for regular Proton.

Reproduction

Add game to steam, select Proton version, install the required runtimes, launch the game. If Proton 11 or up was selected, game throws a warning that 10.0.9 x86 is not installed. If Proton 10 or older is selected, the game runs fine.

steam-15719751810027618304-working.log

  • Another log, this time with GE 10-34 selected with the same prefix and launch settings.
Kkisak-valve maintainer 2026-09-16 github

Hello @immyj-trv, 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/6702#issuecomment-5698655399.

Iimmyj-trv 2026-09-16 github

@kisak-valve should I maybe file this one as a general compatibility issue? Doesn't really matter what game this is, Proton is simply failing to use the installed .NET runtime, and since older versions work fine I see this as a regression

Kkisak-valve maintainer 2026-09-16 github

In general, we're organizing feedback on this issue tracker by game title. #6702 is the right place for all feedback related to that game, including regressions.

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