The VAC system was unable to verify the Counter-Strike: Global Offensive session - fixing the problem

 Counter-Strike: Global Offensive is a popular competitive first-person team shooter. Recently, players have been complaining that they are facing the error “VAC was unable to verify your game session”. Today we will tell you why this problem occurs and how to solve it.

Restart the Steam client

One of the easiest solutions to a problem. During a gaming session, a large number of processes take place. If the system does not have time to process them, a failure may occur. In this case, do the following:

1. Launch Steam.
2. In the upper right corner of the screen, you will see your account nickname and an arrow next to it. Click on it.
3. Select Sign Out.
4. Enter your details and log in again.

Restart your computer

This method will help players who rarely turn off their PC or those who previously logged into their Steam account on another device. Restarting your computer or laptop will update all processes and running programs.

Run the game as an administrator

To do this, you will have to find the csgo.exe executable file :

1. Go to your Steam Library and select a game.
2. Right-click and select "Manage", then click on the option to view local files.
3. In the folder that opens, find the csgo.exe application, click on the RMB file, and select "Properties".
4. Go to the "Compatibility" tab.
5. Check the box "Run this program as an administrator", then save the changes.

Check the integrity of game files

When faced with an error, the most rational solution is to check the integrity of the files. During the scan, the client will check that the necessary files are missing and redownload them. To run a check, follow the steps below:

1. Open the game library.
2. Select an application and right-click. An action window will appear with the selected game.
3. Click "Properties".
4. Select "Local Files".
5. Click on the "Check File Integrity" button.

Repair Steam using the command line

Another reason for the error can be a crash of the Steam servers. In this case, we advise you to use the command line. Follow the instructions below to restore the client:

1. Use the combination "Win + R" to open the search.
2. Type "cmd" without the quotes and click OK.
3. To start the recovery process, you will need to enter a command.

"Path to the Steam folder and the file SteamService.exe" /repair, for example:

• "C:Program Files (x86)SteambinSteamService.exe" /repair

As in the previous case, you will have to wait until the computer has completely processed all the data and downloaded the missing files. Restart your computer after the check is complete. Open the client again and start the game.

Disable your antivirus

The process of scanning the system with an antivirus can be a factor that causes this error. System protection affects the operation of VAC when checking and restoring applications in the background. 

If you do not want to completely disable protection, you can try adding the Steam.exe process to the exceptions. A similar function can be found in the settings of any antivirus software.

End tasks running in the background

Some VPN or Proxy processes may conflict with Valve Anti-Cheat, which in turn leads to an error. Below we will describe the most common programs that interfere with the launch of Valve anti-cheat.

Services

Using the key combination "Win + R" open the window "Run". Enter "Services.msc" without quotes and click OK. The Services application will open.

Find the following services:

• VMnetDHCP;
• VMUSBArbService;
• VMware NAT Service;
• vmware hostd;
• VMAuthdService;
• hshld.

Right-click on each of them and select Disable.

Processes

Press the key combination "Ctrl + Shift + Esc" to open "Task Manager". Go to the "Processes" tab. Find and end the following processes (if any):

• hydra.exe
• hsswd.exe
• hsscp.exe
• vmware.exe.

Right-click on each of them and select " End Task".

Steamservice.dll error

Sometimes this error is related to Steamservice.dll files. One file is stored in the Steam client directory, and the second is stored in the Program Files (x86) folder on the system drive. They must be identical, otherwise, it may cause a problem when checking files with Valve's anti-cheat. It is worth noting that the file in the directory with the client will always be up-to-date, so you need to replace the second DLL file with it:

1. Navigate to the Steam root folder along the path "Drive: / Steam/bin".
2. Copy "Steamservice.dll" .
3. Go to the "System Drive: / Program Files (x86) / Common Files / Steam" folder and replace the similar file with the copied one.

Reinstall the game

If none of the above methods helped you, try reinstalling Counter-Strike: Global Offensive. In this case, the installed configs for the game will be deleted, so we strongly recommend that you save them to a separate folder. The configuration is stored along the path:

• "Drive:/Program Files (x86)/Steam/steamapps/common/Counter-Strike: Global Offensive/csgo/cfg"

Go to the directory and save the configuration to any location on your hard disk if it has been changed manually. After reinstalling the game, place the files in the "cfg" folder.

Update your video card driver

A similar error also occurs due to an outdated version of the video adapter drivers. Go to the website of the graphics chip manufacturer ( NVIDIA or AMD ), download, and install the latest drivers.

Exit Steam Betas

Perhaps you once included a beta version of the client and forgot about it. This factor can affect VAC and gameplay. You can disable the beta version as follows:

1. Launch Steam.
2. Click on the inscription "Steam" in the upper left corner of the screen, then select "Settings".
3. Click on "Account".
4. In the "Beta testing" section, click on the "Change ..." option and select "REJECT - Exit all beta programs".
5. Save your changes.