System Information

• OS: Arch Linux
• Kernel: 6.15.9-arch1-1
• GPU: AMD Radeon RX 9070 XT (Navi 48, PCI ID 08:00.0)
• GPU Driver: Mesa 25.1.7-arch1.1
• Desktop Environment / Window Manager: Hyprland (Wayland)
• Steam Client Version: 2025-05-01
• Proton Versions Tested: Proton 10, Proton 9, Proton Hotfix
• Steam Runtime: Steam Linux Runtime 3.0 (Sniper)
• Steam Beta Participation: No
• System Up to Date: Yes

Issue Description

Counter-Strike 2 fails to join official matchmaking when using Proton on Arch Linux with Hyprland. The game launches without any issues, but attempting to find a match results in:

“VAC was unable to verify your game files.”

Steps to Reproduce

1. Install Steam and Counter-Strike 2 on Arch Linux.
2. Set the game to use Proton 10, Proton 9, or Proton Hotfix via Steam’s compatibility options.
3. Launch the game and attempt to start official matchmaking.
4. Observe the VAC verification failure.

Expected Behavior

VAC should verify the game session successfully under Proton so that matchmaking functions properly.

Additional Notes

• Game works in offline mode and community servers.
• Game functions under Steam Linux Runtime, but resolution issues occur under Hyprland.
• Game files have been verified in Steam — no effect.
• Issue appears to be specific to CS2 + Proton combo.