Fix CS2 'VAC was unable to verify your game session'

Updated: 11/29/2025

You queue for Premier Mode, and the red text appears: 'VAC was unable to verify your game session'. You aren't cheating, so why is Valve blocking you? This error happens when the Valve Anti-Cheat (VAC) system cannot read its own security files on your PC, usually because they were modified by a disk cleanup tool or blocked by Windows permissions.

Method 1: Verify Integrity of Game Files

This checks if any VAC signature files are missing and redownloads them.

• Open Steam Library.
• Right-click Counter-Strike 2 > Properties.
• Go to Installed Files > Click Verify integrity of game files.
• Wait for it to reach 100% and then restart Steam.

Method 2: Repair the Steam Service (CMD)

Sometimes the Steam background service itself is broken. You can force a repair using the Terminal.

Step 1: Close Steam

Make sure Steam is not running in the taskbar.

Step 2: Run Command

Press Win + R and type this exact path (include quotes):

A black window will pop up and close quickly. Launch Steam as Administrator afterwards.

Method 3: Change Steam Profile Name

It sounds like a myth, but changing your profile name forces the Steam network to refresh your account's session token.

Go to your Profile > Edit Profile. Change your display name slightly. Save. Try queuing for a match. This often 'unsticks' the verification loop.