LoL Guide: How to Fix “A Critical Error Has Occurred” & “Unexpected Login Session” Errors

League of Legends may be a popular MOBA, but it’s not immune to occasional bugs. Two common errors players face are the “Unexpected error with the login session” and “A critical error has occurred.” This guide will help you get back to dominating the battlefield.

LoL Guide: How to Fix “A Critical Error Has Occurred” Error

The “A critical error has occurred” message can appear when launching the League of Legends client or during gameplay. It causes both the client and game to crash, accompanied by an operating system error message.

Riot’s Recommended Fix

Riot Games, League of Legends’ developer, suggests a solution that tackles overlay programs interfering with the game. Here’s what to do:

  1. Open Task Manager using Ctrl+Alt+Delete.
  2. End processes for any program with overlay features, such as Discord or Steam.
  3. Delete the “Config” and “Logs” folders within your League of Legends directory.
  4. Relaunch the League client.

Alternative Solution

If the above solution doesn’t work, fret not! Here are other methods that have helped some players:

  1. Right-click the League of Legends.exe file, go to Properties > Compatibility, and enable “Run this program as administrator” and “Disable fullscreen optimization.” Repeat for LeagueClient.exe.
  2. Temporarily disable your firewall or antivirus to see if it’s causing the issue. Remember to re-enable them afterward for protection.
  3. Outdated graphics drivers can sometimes cause errors. Update them to the latest version.
  4. Use the built-in repair tool within the League client to scan and fix corrupted game files.
  5. If all else fails, a complete reinstall might be necessary.
Critical Error lol
Image via Riot Games

Lol Guide: How to Fix “Unexpected Login Session” Error

This error message indicates a hiccup in communication between your game session and Riot’s servers. Thankfully, there are several solutions you can try.

Riot’s Recommended Fix

  1. With the League client open, press Alt+F4.
  2. Choose “Sign Out” instead of “Exit.”
  3. Use Ctrl+Alt+Delete to launch Task Manager.
  4. In Task Manager, end all processes for:
    • Riot Games Launcher
    • RiotClientServices.exe
    • LeagueofLegends.exe
  5. Reopen League of Legends through the launcher and log in again.

Alternative Solutions

  • DNS Server Fix: If Riot’s solution doesn’t work, consider changing your DNS server. Online resources can guide you through this process.
  • Language Setting Check: Some players report the error coinciding with an unauthorized language change in the client. Try reverting or changing the language settings and relaunching.
  • VPN Toggle: Enabling or disabling a VPN has helped some. If you use a VPN, try accessing the client without it. If other solutions fail, a VPN might be the key.

By following these steps, you should be well-equipped to vanquish these common League of Legends errors and return to dominating the Rift!