How to Fix "VAC Was Unable to Verify Your Game Session"

Method 1: Verify Game Files

1. Open Steam Library
2. Right-click Counter-Strike 2 -> Properties
3. Installed Files -> Verify integrity of game files
4. Wait for it to complete and download missing files.

Method 2: Restart Steam as Administrator

Sometimes Steam Service doesn't have permissions to run the VAC check. Close Steam completely, right-click the icon, and select "Run as Administrator".

Method 3: Repair Steam Service

Open Run (Win+R), type: "C:\Program Files (x86)\Steam\bin\SteamService.exe" /repair