How to fix “VAC was unable to verify your game session” error on Steam for Windows

by Arthur · November 3, 2022

When trying to matchmake in a Steam game, do you get the error message “VAC was unable to verify your game session”? In most cases, it occurs when you try to enter the game with a cheat or hack enabled. However, Steam sometimes raises a false flag when you’re just trying to play fair, resulting in this error message.

But what exactly is this VAC that could not verify your gaming session? In this article, we will discuss this error in detail and provide solutions that you can use to fix it.

Table of Contents

What does the “VAC was unable to verify your game session” error mean?

To understand what this error message represents, you need to understand how VAC works. VAC, known as Valve’s Anti-Cheat, is a software program developed by the same company, Valve, which owns many popular Steam games, including Counter-Strike, Day of Defeat, etc.

This software works with Steam and hunts players who try to enter the game session with a hack or cheat software enabled. Not only does it detect an unauthorized program or script running with the game, but it also detects any changes to the game files. When the software detects unfair play, it immediately bans the user.

In light of this, the error message “VAC was unable to verify your game session” means that VAC, an anti-cheat program, was unable to verify your game session because it detected some tampering in your game files or detected a third-party program or script which attempted to change game processing.

When you encountered this error, were you running such a program or did you make unauthorized changes to the game files? If so, make sure VAC hasn’t banned you.

First, make sure you are not VAC banned

The most common reason for this error message is that you may have received a VAC ban. It is therefore advisable to rule this out first. Follow these steps to verify:

Sign in to your Steam account.
Click on the top left Steam and choose Settings.
Click on in the left sidebar Accounting the tab.
In the right pane, check VAC status.

If it says “No VAC ban on account,” there is no VAC ban on your account. If it says you’re banned, go to the VACBanned website, enter your SteamID in the search field at the top right, and press enter. The VACBanned engine checker will show you when you received the VAC ban.

Check the VAC status of an account on the VACCanned site by entering the Steam ID in the search field

If it was recently placed and you’re sure you didn’t do anything wrong, it may be automatically removed once the investigation by the Steam Support team is complete. As for Steam Support’s investigation time frame, no information has been provided as to how long it will take. So let’s wait a few days and see what happens.

Still, if it has been there for a long time, the investigation may already be complete. There is no way to appeal VAC bans, so you may only have the option to create a new account.

Now, perform some preliminary checks…

If you are not banned, perform the following preliminary checks to rule out minor errors:

Exit the game session, restart the game and try matchmaking again.
Restart the Steam client.
Log in to your Steam account again after logging out.
Restart your Windows device.
Disable Windows Defender or any other antivirus you use, or whitelist the Steam client and directory folders.
If you have been using a VPN, now is the time to turn it off.
Make sure your Steam client and game are up to date.
Make sure your operating system is up to date.

If none of these checks help, it’s time to dig deeper.

1. Run Steam as administrator

VAC may not verify your game session because Steam cannot access specific game files. To rule this out, give Steam exclusive access to all system files by running it as administrator. To do so, right-click on the Steam shortcut and click Run as administrator.

Run Steam client as administrator by right-clicking on the Steam shortcut on the Windows desktop

Apply the following fix if you continue to receive the error.

2. Run the game as administrator

For the same reason we gave Steam client administrator rights, you should run CS:Go or any other game as an administrator to ensure that restricted access does not result in the error under discussion. Here are the steps you need to follow:

Paste the following path into Windows File Explorer:
```
C:\Program Files (x86)\Steam\steamapps\common
```
Open the folder of the game you are having problems with.
Find the game’s executable file.
Right click on it and select Properties.
Navigate to Compatibility tab i Properties window.
Tick the box for Run this program as administrator.

3. Exclude interference from other programs

While you may only get banned or receive the discussion error when trying to enter a game session hosted on a VAC-protected server with a cheat, it is possible to encounter this error even when playing other single-player or offline games where cheating is allowed.

So make sure you don’t run a cheat program for Steam games other than CS:GO. If you are, you should close it temporarily. Likewise, you should make sure that no such background apps or tasks are running, which you may not see but may be causing the error. For reference, see our guide on how to disable background apps in Windows 11.

If the error persists after closing such programs, apply the next fix.

4. Verify the integrity of the game files

The “VAC was unable to verify your game session” error may occur due to incorrect installation of the game files. This means that you may not be running any cheats or making unauthorized changes to the game files, but Steam may consider improperly installing files as a violation of the VAC policy. As a result, you get an error message.

To rule out this possibility, you should verify the integrity of the game files, which can be done through Steam. Here are the steps you need to follow:

Sign in to your Steam account.
Right-click the game you are encountering the error with and select Properties.
Click on in the left sidebar Local files the tab.
Click on in the right pane Verify the integrity of the game files.

5. Switch to offline mode and back to online mode

If verifying the integrity of the game files doesn’t work, you can try a rather unusual but handy solution by switching between Steam’s offline and online modes once. Performing this step will ensure that any temporary issues with the game’s connection are not the cause of the problem. Here are the steps you need to follow:

Start Steam and log in.
At the top left, click on Steam the tab.
click on Log off.
Click Enter offline mode.
Please wait a few minutes.
Go back to Steam tab, and click Go online.
Click Exit offline mode.

6. Repair the Steam Library folder

Repairing the Steam Library folder also has a good chance of fixing the problem. Follow these steps to run the repair as a last resort:

Sign in to your Steam account.
Click on the top left Steam and choose Settings.
Click on in the left sidebar Downloads the tab.
Click on in the right pane Steam library folders.
Next to a storage space, click on three horizontal dots.
Hit Repair folder.

Once the folder is repaired, run Steam again to see if the issue is resolved.

Reinstall all affected games and Steam

If the problem persists, it may be necessary to reinstall the games you are experiencing the error with. If you’re not sure how to do that, check out our guide on how to uninstall and reinstall Steam games for more information.

If that doesn’t work, reinstall Steam. Uninstalling Steam will delete all your games, including their saves. So be sure to back up your saves or make sure they’re uploaded to the Steam Cloud before proceeding.