This error is caused by VAC (Valve’s Anti-Cheat) software when it deems that your account has violated Valve’s terms and conditions. But you might also see this error due to some server error or if you’ve recently made changes to your game files.
How to Fix “VAC was unable to verify your game session” Error
First things first, you need to make sure that your account is not banned due to the use of third-party hacking software or scripts. If you’re caught using these software, you can kiss your account goodbye. However, if you think you’re seeing this error by mistake, you can try these methods to fix it.
Verify CS: GO Game Files Integrity
Sometimes when you update the game, there might be some corrupted files. Or, you might have accidentally deleted some files while you were browsing File Explorer. Whatever the case, it can cause serious issues in your game when something like that happens. Verifying integrity of game files ensures that there are no faulty files or missing files in the game’s directory. To verify your game files integrity: You might need to wait for a while for this process to be completed. After it is completed, restart your PC and try to launch CS: GO again. You should be able to play the game normally now. However, if the problem persists, you can try other methods mentioned below.
Close Steam and Relaunch It as Administrator
Your apps start to misbehave when they don’t get the permissions they need. So to make sure they get all the permissions they need, launching them as administrator is the best choice. Launching Steam as an administrator usually fixes this issue. To force close Steam: To launch Steam as Administrator: Now, try to launch CS: GO and see if the problem is gone. If the problem still persists, you can move on to other methods.
Restart Your Windows
In times of any issues or problems, restarting your Windows can be a life-saving option. Restarting Windows fixes many glitches caused by programs, and surprisingly it seems to fix this particular issue as well.
Log out from Steam and Re Login Again
Relogging in fixes some glitches and errors you’re having with Steam. To try this method: Now, launch CS: GO and see if it runs normally.
Repair the SteamService.exe
One of the reasons you could be facing this problem is when you have corrupted files in the Steam directory. It is recommended that you perform this method at a regular interval of time to make sure that there are no broken or corrupted files in Steam. To do that: After you press Enter, you’ll see an empty terminal in your Windows which will run a bunch of scripts. The terminal closes by itself when the script is run, and you don’t need to do anything. Just wait for it to complete and restart Steam after it’s done. Try launching CS: GO now and see if the problem is gone.
Exclude Your Anti-Virus from Scanning CS: GO Directory
As you know, anti-virus can cause a lot of problems on your PC if you haven’t configured it well. So if you’re getting a VAC error message out of nowhere, chances are your anti-virus accidentally marked your game files as a virus. Now, there isn’t a sure way to know that this issue is caused by your anti-virus. However, you can exclude the directory of CS: GO and try launching the game again. If it runs normally after that, you may need to apply some settings to the anti-virus.
Reinstall CS: GO
If none of the methods seem to work for you, you can always reinstall the game. Keep in mind that this should be done as the absolute last resort when nothing works. Wait for this process to complete and restart your PC after that. After restart, launch Steam and install CS: GO again. Now, your issue should be fixed, and you should be able to play the game normally. That’s it! These are all the methods that will help you get back to your game. These methods usually work for most people, but if you’re still experiencing the issue, you can try updating your drivers, letting Steam and CS: GO through the Windows Firewall, or even updating Windows.