The VAC Authentication Error on Counter Strike Global Offensive is an especially notorious one not only because nobody truly knows what causes it, but also because it can cause you to be kicked out in the middle of games. Let’s take a look at some of the possible fixes for this error.
Turn off your hacks.
If you’re using some illegitimate hacking software, disable it. Seriously, there is a very good chance that this is causing your error.
Optimize your storage.
Delete any and all software on your computer that you do not need. It is possible that there is some sort of malware hiding in there, or just plain dead weight causing the game to misbehave.
Enable the No-Execute bit.
If you are using an Intel Processor, go into its settings and look for “XD Bit” and enable it. On AMD processors, the same setting will be called the “NX Bit”. Explaining what this does would be an entirely different article, but you can find out more about it here.
Uninstall or suspend conflicting programs
Steam maintains a list of conflicting programs that can cause it to misbehave. This includes anti-virus software, VPN software, and P2P clients. To find out how you can prevent these applications from interfering, see here.
Repair the Steam service
Click on the Start button and search “Run”. In the dialog box, type in this command: 2 “C:\Program Files (x86)\Steam\bin\SteamService.exe” /repair. Launch the game and see if this fixed your error.
Verify integrity of game files.
Open up Steam and go to CS:GO’s library page. Here, select “Manage” and then “Properties”. Navigate to the “Local Files” tab and click on “Verify integrity of game files…”. Once this is done, it will automatically replace any files that have been corrupted. Now, reboot your device and open the game again to see if this error was fixed.