VAC error / Game Security Violation in CS2
Step-by-step guide on what to do if VAC was unable to verify the game session (verifying file integrity, clearing the Steam cache, closing conflicting programs).
To fix the VAC / Game Security Violation error ("VAC was unable to verify the game session"), go through a few steps:
Verify file integrity: In Steam open CS2 → Properties → Local Files → Verify integrity.
Clear the Steam cache: Settings → Downloads → Clear download cache.
Close conflicting programs: Close Discord Overlay, MSI Afterburner, antivirus software with active protection and any third-party overlays.
Restart the client: Run Steam and CS2 as administrator.
Reinstall: If nothing helps, reinstall CS2 or Steam itself.
So the steps go from checking the files to removing conflicts and a full reinstall — this is the standard order of steps that most often solves the problem.
