7 Ways to Fix the League of Legends Critical Error on a Windows PC

Many League of Legends players have reported the critical error that crashes the game when they try to start LoL multiplayer matches. The error message says, “A critical error has occurred and the process must be terminated.” This issue has blighted League of Legends players for years and makes the game unplayable. Fortunately, LoL players have found ways to fix the critical error. These are some ways you may be able to fix the League of Legends critical error on a Windows PC.

Run League of Legends as an Administrator

First, try applying simpler potential resolutions for the League of Legends critical error like running the game as an administrator. This will ensure LoL has full Windows system access. You can set League of Legends to always run as an administrator like this.

1. Open the Explorer folder navigator (activated by the Windows logo + E hotkey) and bring up the League of Legends installation folder.
2. Next, open the Games subfolder in the League of Legends directory.
3. Right-click the League of Legends EXE (application) file to select Properties.
4. Click Compatibility within the tab bar.
5. Select the Run this program as administrator and Disable fullscreen optimization checkboxes.
   
   

   The Compatibility tab

6. Click Apply and select OK to set the changed settings.
7. Repeat those steps for the LeagueClient file in the League of Legends folder to set that software to run with admin rights. However, don’t select to disable fullscreen optimization for the LeagueClient software.

Erase the League of Legends’ Config and Log Folders

Some LoL players confirm that erasing the Config and Log data folders can resolve the League of Legends critical error. This is how you can erase those folders.

1. Bring up Explorer and the League of Legends directory, which has this default path: C:\Program Files\Riot Games\League of Legends.
2. Next, right-click the Config folder and select Delete.
   
   

   The Delete context menu option

3. Right-click the Logs folder to select its Delete context menu option.

Update the Driver for the Graphics Card

1. Bring up a web browser and go to the NVIDIA or AMD driver download webpage.
2. Select your Windows OS and graphics card model on the selection menus.
   
   

   The NVIDIA driver download page

3. Press the Search or Submit button.
4. Click Download for the latest graphics driver.
   
   

   The Download button

5. Go into File Explorer to open the folder containing the downloaded NVIDIA or AMD graphics driver package.
6. Double-click the AMD/NVIDIA file to bring up a setup wizard from which you can install the graphics driver.

Of course, you’ll need to be clear about what your PC’s graphics card model is to update its driver as outlined above. To check, activate the Windows search tool by clicking on its icon or box on the taskbar, enter dxdiag, and select to open dxdiag from there. The Display and System tabs in the DirectX Diagnostic Tool include graphics adapter and platform details.

Turn Off Antivirus Sheilds

Your antivirus software could be causing the League of Legends critical error by wrongly flagging legitimate and blocking the game from running. Users who don’t have third-party antivirus apps can disable Microsoft Defender to ensure it’s not causing any issues. This Microsoft page includes guidelines for disabling the Defender antivirus. Try running League of Legends again after disabling the antivirus shield.

The Real-time protection option in Windows Security

Third-party antivirus tools override Microsoft Defender. To turn off a third-party security app, you will need to right-click its system tray icon and select an option that turns off its antivirus shield. Select a temporary option for disabling the antivirus shield for a few hours if you can.

Allow League of Legends Through Microsoft Defender Firewall

A few LoL players have said they fixed the critical error crashing issue by adding League of Legends to the allowed list for the Windows firewall. Doing that will ensure Microsoft Defender Firewall isn’t blocking the game from connecting to servers. To apply this potential resolution, follow the instructions on this Microsoft support page. Add the League of Legends EXE file to the allowed list and select the Private/Public checkboxes for it.

The Allowed apps firewall

Reinstall League of Legends

Reinstalling League of Legends could fix the critical error issue if there are corrupted game files. LoL has a Hextech Repair Tool with which you reinstall the game as follows.

1. Open the Hextech Repair Tool download page in the Windows Edge browser.
2. Click Download for Windows on that webpage.
3. Press Edge’s Ctrl + J keyboard shortcut.
4. Click the Hextech Repair Tool.msi file within Edge’s Downloads list to run that setup wizard and install the software.
5. Run the Hextech Repair Tool.
6. Click the Reinstall checkbox to select that setting.
   
   

   The Hextech Repair Tool software

7. Press Start in the Hextech Repair Tool window.

Uninstall GeForce Experience

The Programs and Features applet

Uninstalling GeForce Experience is a potential resolution for the League of Legends critical error some players have confirmed to work. Do you have GeForce Experience installed on your Windows PC? If so, uninstalling that software could be a possible solution for the LoL critical error. This Uninstall or remove apps page on the Microsoft site provides details about how to uninstall Windows software.

There’s a pretty good chance those potential solutions will fix the League of Legends critical error on your Windows PC. However, nothing is guaranteed because the LoL critical error is not always a straightforward issue to fix. If you need further troubleshooting methods for this issue, send a support ticket to League of Legends support from this Submit a request page.