If you are trying to play CS: GO and all of a sudden, a VAC Game session error pops up on your screen you are not alone. Many CS: GO players have encountered this problem with matchmaking.
As you know, being unable to enter matchmaking is really frustrating because you can’t play the game. You are stuck on the home screen with nothing to do.
Lucky for you, this problem with VAC is very easy to fix. Follow the guide below to help you solve this problem.
Method 1: Restart your Steam Client
You can get this error because there are some instances where steam encounters a bug or error within its system. Restarting the client will help you in resolving this issue.
Step 1: On your steam client, click on Steam on the menu bar
Step 2: Click on exit
Step 3: Open Steam Client
Step 4: Click on Steam again on the menu bar
Step 5: Select Go Offline
Step 6: Now a pop-up window will appear, Press Restart in Offline Mode
Step 7: After restarting steam, click on Steam again on the menu bar
Step 8: Click on Go Online
Step 9: Then, click on Restart and Go Online
Method 2: Verify Integrity of Steam Game Files
Step 1: Open Steam
Step 2: Log in to your account
Step 3: Go to Library
Step 4: Right Click on the game that you are having problems launching
Step 5: Click on Properties
Step 6: Click on the Local Files tab
Step 7: Click on Verify Integrity of the game
Step 8: Wait for the process to finish
Method 3: Repair Steam Client in CMD
Step 1: Press on Windows key + S and Search for Command Prompt
Step 2: Click on Run as Administrator
Step 3: On Command Prompt, Type the following lines and hit Enter
“C:\Program Files (x86)\Steam\bin\SteamService.exe” /repair
Step 4: After repairing Steam, try to run CS: GO again and see if the problem is fixed
See Also: What to Do When Steam Won’t Open