5 Ways to Fix League of Legends Error 004 on a Windows PC

League of Legends error 004 is an issue many LoL Windows PC players have encountered over the years. This error occurs when the LoL client tries to install patch updates. The error 004 message says: “Patching failed and we’re not sure why. Please restart the client to try patching again. (Error code 004).” Consequently, the League of Legends client doesn’t start because it can’t install the required updates and players can’t play LoL. This is how you can fix League of Legends error 004 on a Windows 11/10 PC.

Read also: 7 Ways to Fix League of Legends Not Launching on a Windows PC

Run League of Legends as an Administrator

First, try applying the simplest of potential fixes like running the League of Legends client as an administrator. You can do that just by right-clicking the League of Legends client Windows desktop shortcut and selecting Run as administrator. If that works, set LoL to always run with admin rights like this.

1. Right-click the League of Legends shortcut on the Windows desktop to select Properties.
2. Click Compatibility to select the Run this program as an administrator option on that tab.
   
   

   The Run this program as an administrator checkbox

3. Select Apply to save the new setting for League of Legends.
4. Click OK to exit the League of Legends properties window.

Free Up Hard Drive or SSD Storage Space

The Run this program as an administrator checkbox

Error 004 can sometimes arise because of limited hard drive or SSD space on a PC. If there is very little storage space available on your Windows PC, try freeing up some hard drive or SDD storage space. The best way to do that is to uninstall unneeded software via the Programs and Features applet or Settings, as outlined on this Microsoft help page. You can also eradicate junk files with the Windows Disk Cleanup tool, which this Microsoft page includes some instructions for utilizing.

Reset Your Network

Resetting network settings is a confirmed way to fix League of Legends error 004, which has worked for many players. You’ll need to re-establish your PC’s internet connection after resetting your network. This is how you reset your network via Settings.

1. Right-click on your Start menu button to select a Search shortcut.
2. Type network reset to find a matching search result.
3. Select Network reset to access that tool.
4. Click the Reset network button.
   
   

   The Reset now button

5. Restart Windows after resetting the network.

Erase Config Files

Many players have also resolved League of Legends error 004 by deleting config files. This involves deleting a game.cfg file and a LoL release version folder. You can apply this potential resolution as follows.

1. Open File Explorer (click on the folder library taskbar button) and go to this folder location: C:\Riot Games\League of Legends\Config.
   
   

   The Config folder

2. Right-click the game.cfg file and select Delete.
3. Next, bring up this directory: C:\Riot Games\League of Legends\RADS\projects\league_client\releases.
   
   

   The releases folder

4. Right-click the folder with the version number to select Delete.
5. Exit File Explorer and open the League of Legends client.

Reinstall League of Legends With the Hextech Repair Tool

Some players have resolved League of Legends error 004 by reinstalling the game client with the Hextech Repair tool. That’s a troubleshooting utility for League of Legends. This is how you can reinstall LoL with the Hextech Repair Tool.

1. Open this Hextech Repair Tool page.
2. Click the Download for Windows option.
3. Open the folder containing the downloaded Hextech Repair Tool.msi file.
4. Double-click the Hextech Repair Tool.msi file to install the utility.
5. Open the Hextech Repair Tool.
6. Select the Reinstall and Clean Uninstall options in the Hextech Repair Tool.
   
   

   The Hextech Repair Tool

7. Also, make sure the Add Firewall Exceptions and Use Public radio buttons are selected.
8. Click the Hextech Repair Tool’s Start button.

One of the potential resolutions outlined above will likely fix League of Legends error 004 on your Windows PC. You can also contact the League of Legends support service about error 004 by clicking the Submit a Ticket button on this Riot Games page. However, try applying the possible resolutions for error 004 in this guide first.