If you are at the moment reading this, then probably you might have witnessed ‘VAC was unable to verify the game session’ type of error randomly occupying the screens of your computer while trying to browse through your Steam account. Steam is a widely popular digital game distribution service provider hosting numerous games in one roof. Many numbers of CS: Go players experience such errors whilst looking forward to finding a perfect gaming match. Witnessing such errors doesn’t mean that you have been banned from entering the gaming session. Configuring the Windows and gaming settings can help in instantly fixing the errors. Keep reading to learn the different methods and steps involved to get rid of steam service error messages any part of the day.

Steps to fix VAC was unable to verify the game session Error

Restarting Steam client in offline mode

If at all the downloaded game-related files have been corrupted or said to be missing due to a malware attack then try restarting the Steam client in offline mode to quickly fix ‘VAC was unable to verify your game session’ type of errors. To restart in offline mode, follow the below-mentioned steps as it is.

1. From the Steam client, click upon the ‘Steam’ option from the top menu section
2. A list shall load-up, make a click on the ‘Exit’ button.
3. Now, the Steam client shall completely close
4. Open back the Steam client
5. Select the ‘Steam’ menu and click upon the ‘Go Offline’ option.
6. Now, you will be prompted with a new window with two different action buttons
7. Select ‘Restart in Offline Mode’ to quickly resolve ‘VAC was unable to verify your game session’ errors.
8. After doing these, again make a left-click on the ‘Steam’ menu
9. From the list, select ‘Go Online’.
10. Click on the action button that says ‘Restart and Go Online’.

Launch your favorite game to re-download the gaming files and to bypass any kind of Steam service errors. If the error persists then try verifying the gaming files by following the upcoming method.

Verifying the gaming files

Integrity issues happening with the downloaded gaming files can easily lead to ‘VAC was unable to verify the game session’ type of issues. Verifying the gaming files is the better way to bypass such issues. 

1. Within the Steam client, click upon the LIBRARY option that can be found below the top-menu icons.
2. Right-click on the game that has been interrupting your gameplay with steam service error messages
3. If at all the Counter-Strike: Global Offensive is one among the game that has been encountering such issues, then right-click on it and then select ‘Properties’ from the configuration list.
4. Within the Properties window, click upon the Local Files tab and then select ‘Verify Integrity of Gaming Files’ from the loaded options.
5. It takes about three or five minutes to complete the entire process
6. Once the files have been successfully verified, click upon the ‘Close’ button.

Re-launch the game and by now the ‘VAC unable to verify game session’ errors must have been bypassed. If you are still witnessing such issues then repair the Steam client using Command Prompt window.

Repairing the Steam client using Windows Command Prompt

The Steam client might have been corrupted due to unknown reasons. Repair it at first to avoid engaging with any kind of Steam service error in the present and future.

1. Exit the Steam client by clicking on the ‘Steam’ menu and then selecting the ‘Exit’ option.
2. Click upon the ‘Start’ button that can be found on the left corner of the taskbar.
3. Within the Search box, type cmd.
4. The ‘Start’ menu shall automatically search for related programs and list Command Prompt under the ‘Best match’ section
5. Right-click upon the ‘Command Prompt’ program and select ‘Run as administrator’ from the showcased list.
6. A new Command Prompt window shall load up with administrator rights that can help in repairing the corrupted files.
7. In the Command prompt window, type as per the below-mentioned image.
8. Press upon the ‘Enter’ button to repair the Steam client file.
9. Close the Command Prompt window 

Open up the Steam client, navigate and launch the game that has been witnessing VAC was unable to verify the game session errors. Repairing the Steam client file must have resolved this particular error. If this method has not fixed the issue then re-install CS: GO game by following the upcoming steps.

Reinstalling CS

GO to fix Steam service error

If none of the above-mentioned fixes has got rid of ‘steam not opening windows 10’ and ‘VAC was unable to verify your game session’ errors, then you need to reinstall CS: GO within the Steam client. Follow the upcoming steps to uninstall and reinstall CS: GO with the recently released CSGO update files. 

1. From the Steam client window, click upon the ‘LIBRARY’ option from the top-menu
2. Find Counter-Strike: Global Offensive from the download games list and make a right-on it using the system connected mouse
3. Click on the ‘Uninstall’ option from the provided configuration list.
4. A prompt window shall get popped-up asking for your permission to delete the CS: GO gaming files from the computer.
5. Click on the ‘Delete’ button 
6. To download CSGO update file, visit www.store.steampowered.com and search for Counter-Strike: Global Offensive download file
7. Download and re-install CS: GO by following the instructions that get mentioned in the installation window

After the installation process gets completed, launch Steam client, load CS: GO and check if the VAC was unable to verify the game session error persists. 

Check for potential performance issues to bypass ‘steam not opening windows 10’ errors

Your Windows 10 running computer system or laptop might be facing performance issues due to various reasons. To quickly fix any type of performance issues in Windows 10 that has been leading to Steam service errors, follow the below-mentioned steps as it is.

1. Open up ‘Control Panel’ from the ‘Start’ menu 
2. You can also open the ‘Control Panel’ using the Run dialog box. Press ‘Windows key’ and letter ‘R’ from the keyboard at the same time to load the Run box. Type control panel and click upon the ‘OK’ button to open Control Panel.
3. Under the ‘System and Security’ section, make a left-click upon ‘Find and fix problems’ option.
4. You will get redirected to the Troubleshooting window
5. Scroll down to the end part of the window and under ‘System and Security’, click upon ‘Check for performance issues’.
6. A new window shall open up, from which you need to click on the ‘Next’ button to let Windows 10 automatically detect for existing performance issues.
7. Once the problems have been identified, a list of possible solutions will get displayed.

Choose the right type of solution to let the Troubleshooting window initiate and fix the Windows 10 performance-related issues that have been triggering VAC was unable to verify the game session error.

Updating device drivers

Steam service error shows up if your device drivers are wrongly installed or said to be out of date. The device drivers can turn obsolete in a short span and might end up being the sole reason to slow up your computer system and to witness VAC errors. 

1. Click on the Windows key from the keyboard to load the ‘Start’ menu
2. In the Search window, type Device Manager
3. Wait for a second until the Start menu automatically searches and loads up relevant programs
4. From the listed search result, click upon ‘Device Manager’.
5. You must provide administrator rights to access Device Manager
6. Click upon the ‘OK’ button from the prompted window to provide the much-needed administrator rights
7. A list of device drivers that need to be updated shall be listed with a yellow colored exclamation point.
8. Make a right-click on the device driver name and from the context list select ‘Update Driver’
9. You can conveniently update the device driver either by automatically searching for recently released update file on the internet or manually download the update file and install the driver software.
10. From the loaded ‘Update Driver Software’ window, click on the option that you find convenient
11. Follow the instructions as mentioned in the update file window 
12. Once the entire device driver software has been updated, launch the Steam client, load CS: GO game to check if the ‘VAC was unable to verify the game session’ errors have been resolved. 

If you are still witnessing such VAC errors in the future, you can again try these fixes one after another or tweet to CSGO’s official twitter handle with the error message screenshots to get instant help.