protonscr

Problems launching the Crusader Kings III and Hearts of Iron IV launcher

protonclosed
ValveSoftware/Proton#9461 · opened 2026-02-03 by salitv1999 · updated 2026-02-03 · 1 comments · github
Ssalitv1999 2026-02-03 github

Compatibility Report

  • Name of the game with compatibility issues:
    Hearts of Iron IV
    Crusader Kings III

  • Steam AppID of the game:
    Hearts of Iron IV: 394360
    Crusader Kings III: 1158310

System Information

  • GPU: AMD Radeon RX 7600
  • Video driver version:
    OpenGL version string: 4.6 (Compatibility Profile) Mesa 26.0.0~rc1+git2601211928.a2b03c2117d~q~mesarc2
  • Kernel version:
    6.17.0-8-generic
  • Link to full system information report as Gist:
    (Not provided)
  • Proton version:
    Proton Hotfix, Proton 10.0-10.03 (other versions not tested yet)

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.

Symptoms

The game launcher does not start.
Steam shows the game as running, but the launcher window does not appear.
Hearts of Iron IV starts only when bypassing the launcher.
Mods (e.g. Millennium Dawn) cause the launcher to freeze or not appear at all.

Crusader Kings III also has launcher issues:
The game does not crash, but the launcher window never appears.
Steam shows the game as running indefinitely.

Reproduction

  1. Install Hearts of Iron IV or Crusader Kings III on Linux via Steam.
  2. Enable Steam Play (Proton).
  3. Launch the game normally through Steam.
  4. Steam shows the game/launcher as running, but no launcher window appears.
  5. Hearts of Iron IV only starts when bypassing the launcher.
  6. Crusader Kings III remains running in Steam without showing the launcher window.

(If anything else is needed, please let me know and I will try to provide the required files, logs, videos, or screenshots.)

Kkisak-valve maintainer 2026-02-03 github

Hello @salitv1999, we're tracking issues with game launchers as part of the game they're launching. Also, 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/4130#issuecomment-3841717800.

Proton versions

Upstream links