League of Legends Error Code 004 is a patching error that appears when the Riot Client can’t complete an update. Client permissions, low storage, damaged game files, connectivity issues, or a temporary Riot-side problem can all cause it.
Worth noting: there have been widespread community reports of Error 004 recurring around recent July 2026 patches. If the error appeared immediately after an update, check Riot’s service status before making major system changes.
Work through the fixes below in order and stop as soon as one works — no need to reset your whole network to fix a stuck background process. (Written for Windows 10 and 11.)
What Causes Error Code 004?
- Client permission problems
- Insufficient storage on the League drive
- Damaged League files after an interrupted update
- Connectivity or DNS problems
- Temporary patch or Riot service issues
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1. Fully Close Riot Client and Restart Your PC
A leftover Riot or League process can prevent the update from restarting cleanly. This sounds too simple to work, but it’s Riot’s first recommended step.
- Close League completely.
- Right-click the Riot Client icon in the system tray and select Quit.
- Open Task Manager (Ctrl + Shift + Esc) and end any remaining Riot/League processes, such as RiotClientServices.exe or LeagueClient.exe.
- Restart your PC and retry the update.
2. Run the Riot Client as Administrator
If the Riot Client lacks the permissions to write or update League files, the patch can fail partway through. Riot’s guidance is to elevate the Riot Client, not the game executable.
- Search for Riot Client in the Start menu.
- Right-click it and select Run as administrator.
- Accept the UAC prompt, launch League, and retry.
You don’t need to leave this permanently enabled — try it once.
3. Check Your Free Disk Space
Riot specifically recommends checking storage on the drive League is installed on (by default C:\Riot Games\League of Legends). If it’s nearly full, there may not be enough room to download and extract the patch files.
Clear some space — old downloads, temp files, or move things to another drive — and retry. To free space quickly, open Settings → System → Storage and check Temporary files/Cleanup recommendations, or search Windows for Disk Cleanup.
4. Run League’s Full Repair
If files were damaged during a previous failed patch, repairing the installation is the next step. It’s worth trying before touching Windows networking.
- Launch League of Legends.
- Click the gear icon in the upper-right corner.
- Click Initiate Full Repair.
- Wait for it to finish, restart the client, and retry.
5. Check Antivirus and Firewall Settings
Third-party antivirus or firewall software can occasionally flag or block Riot’s files mid-patch. You don’t need to disable your security software entirely — just make sure it’s not interfering.
First, check your antivirus’s quarantine or protection history for a blocked Riot Client or League file, and restore/allow it if found. Then add the Riot Client and League executables to your firewall’s allowed-app list; if your antivirus supports folder exclusions, add the Riot Games/League installation folder too. Retry the patch afterward.
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6. Reset Winsock, TCP/IP, and DNS
If a network-stack or DNS problem is interfering with the connection, reset Windows networking before a full Network Reset — it’s far less disruptive.
If you’re using a VPN or proxy, disable it and retry first; Riot recommends connecting without one when troubleshooting. If your connection seems generally unstable, restart your modem/router, pause large downloads, and try Ethernet instead of Wi-Fi.
- Search for Command Prompt, right-click, and Run as administrator.
- Run these one at a time:
netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns
- Restart your PC and retry.
7. Change to a Public DNS Server
If flushing DNS didn’t help, your current DNS server may be struggling to resolve Riot’s services. If flushing DNS didn’t help, you can try Google’s public DNS servers:
Preferred DNS: 8.8.8.8
Alternate DNS: 8.8.4.4
- Open Control Panel → Network and Internet → Network and Sharing Center.
- Click Change adapter settings.
- Right-click your active connection → Properties.
- Select Internet Protocol Version 4 (TCP/IPv4) → Properties.
- Choose Use the following DNS server addresses and enter the ones above.
- Click OK, close the windows, and restart the Riot Client.
8. Install Pending Windows Updates
League currently supports Windows 10 build 19041+ and Windows 11. If your installation is below that, update it. Otherwise, it’s still worth installing any pending Windows updates and restarting before retrying.
Community-reported tip: some players have found that installing a pending hardware/driver update (Windows Update → Advanced options → Optional updates) and restarting resolved the patch failure. Not Riot’s official fix, but worth trying.
Still stuck after a recent patch? Multiple players report that reinstalling Riot Vanguard fixed Error 004 when restarting, Full Repair, and admin mode didn’t. This is a community-reported workaround, not one of Riot’s primary Error 004 fixes:
- Close all Riot/League processes.
- Uninstall Riot Vanguard via Settings → Apps → Installed apps.
- Restart your PC.
- Launch the Riot Client and League again and allow Vanguard to reinstall. Restart the PC again if prompted, then retry the update.
9. Perform a Windows Network Reset
Try this only if the fixes above haven’t worked. A full network reset removes and reinstalls your network adapters, restoring their settings to defaults. It can help with persistent network configuration problems, but it’s the most disruptive fix here — you may need to reconnect to Wi-Fi and reconfigure VPN software or virtual switches afterward, and networks may revert to “Public.”
- Windows 11: Settings → Network & internet → Advanced network settings → Network reset → Reset now
Windows 10: Settings → Network & Internet → Status → Network reset
Confirm when prompted, let your PC restart, reconnect, and retry the update.
10. Reinstall League of Legends
If nothing else has worked, a reinstall clears out anything a repair couldn’t fix.
- Fully close League and the Riot Client.
- Open Settings → Apps → Installed apps, find League of Legends, and uninstall.
- Restart your PC.
- Download the latest installer from Riot’s site and reinstall.
For a completely clean reinstall, Riot also provides a deeper cleanup procedure covering remaining Riot Client, AppData, and ProgramData files — be careful with this if you have other Riot games installed, since some data is shared between titles.
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Still Seeing Error Code 004?
If the error persists after all of the above, avoid making increasingly invasive changes. Instead, check whether Riot has reported a service issue, run the Riot Repair Tool to collect your League logs, and submit them to Riot Support along with what you’ve already tried. At that point, Riot’s support team is better equipped to diagnose it than another round of guesswork.
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Frequently Asked Questions
What does League of Legends Error Code 004 mean?
League of Legends Error Code 004 is a patching error that appears when the Riot Client cannot complete an update. It can be related to permissions, insufficient storage, damaged League files, connectivity problems, or temporary patch/service issues.
How do I fix Error Code 004 in League of Legends?
Start by fully closing the Riot Client and restarting your PC. If that does not work, run the Riot Client as administrator, check your free disk space, use League’s Full Repair, check firewall or antivirus settings, troubleshoot your connection, install pending Windows updates, and reinstall League as a last resort.
Why does League of Legends say “Patching Failed” with Error Code 004?
The message appears when the Riot Client fails to finish downloading or installing a League update. Common problems include blocked file access, insufficient storage, damaged game files, or a connection problem interrupting the patching process.
Is League of Legends Error Code 004 a Riot server issue or a problem with my PC?
It can be either. Most troubleshooting focuses on local issues such as permissions, storage, files, and networking, but Error 004 has also appeared around recent League patches. Check Riot’s service status before making major changes if the error started immediately after a new update.
Can low disk space cause League of Legends Error Code 004, and how much free space do I need?
Yes. Riot recommends checking the drive where League is installed because the patch needs enough room to download and extract files. There is no fixed amount of free space that guarantees a fix, so free additional storage if the League drive is nearly full.
Does running the Riot Client as administrator fix Error Code 004?
It can. Running the Riot Client as administrator gives it elevated permissions to write and update League files. Use the administrator option on the Riot Client rather than permanently enabling admin rights on the League game executable.
How do I repair corrupted League of Legends files when the patch fails?
Launch League of Legends, click the gear icon in the upper-right corner, and select Initiate Full Repair. Let the repair finish, restart the client, and retry the update.
Can antivirus or firewall software cause League of Legends Error Code 004?
Yes, security software can sometimes block Riot Client or League files or prevent the client from communicating correctly. Check your antivirus quarantine or protection history and add the Riot Client and League executables to the appropriate firewall or antivirus exceptions if necessary.
Can a bad internet connection, VPN, or proxy cause LoL Error Code 004?
Yes. Connection problems can interfere with patch downloads. Disable any VPN or proxy, restart your router if necessary, pause large downloads, and try a wired connection instead of Wi-Fi if your network is unstable.
Does flushing or changing DNS fix League of Legends Error Code 004?
It can help when DNS or Windows network configuration is interfering with Riot Client connectivity. You can flush DNS with ipconfig /flushdns and, if necessary, switch to a public DNS such as Google’s 8.8.8.8 and 8.8.4.4.
How do I reset my network settings to fix Riot Client patching problems?
Start with a targeted network reset by running netsh winsock reset, netsh int ip reset, ipconfig /release, ipconfig /renew, and ipconfig /flushdns in an administrator Command Prompt. If the problem continues, Windows Network Reset can remove and reinstall your network adapters and restore their settings to defaults.
Can updating Windows or my drivers fix League of Legends Error Code 004?
It can in some cases. Install pending Windows updates and restart your PC before retrying the patch. Some players affected by recent Error 004 problems have also reported success after installing optional hardware or driver updates through Windows Update.
Does reinstalling Riot Vanguard fix League of Legends Error Code 004?
It has worked for multiple players affected by recent Error 004 patching problems, but it is a community-reported workaround rather than one of Riot’s primary fixes. Uninstall Riot Vanguard through Windows Installed Apps, restart your PC, launch Riot Client and League again, and allow Vanguard to reinstall.
Do I need to reinstall League of Legends to fix Error Code 004?
Usually not. Restarting the Riot Client, running it as administrator, freeing disk space, repairing League files, and fixing network or firewall problems should all be tried first. Reinstall League only if the earlier fixes fail.
What should I do if League of Legends Error Code 004 still won’t go away?
Check Riot’s service status and avoid increasingly invasive Windows changes. Run the Riot Repair Tool to collect your League logs, then submit those logs to Riot Support along with a list of the troubleshooting steps you have already tried.
