Avast Blocking League of Legends: 6 Ways To Easily Fix It

Along with DOTA2, League of Legends (or LoL) is among the most popular MOBA-style games. Originating from a modified game mode in the classic Blizzard title Warcraft 3, LoL has become an absolute force in the gaming space.

LoL is what’s known as a F2P (free to play) game. Because of this, it’s proven to be very popular and has a huge player base. However, because people can make new accounts, they must be pretty tight about their anti-cheat detection to ensure the game environment stays positive for players.

This can lead to Avast blocking League of Legends for many users. Today we’ll show you how to unblock League of Legends so you can resume playing right away.

Why is Avast blocking League of Legends?

While there are several things that can cause this issue, one of the most common is that League of Legends’ anti-cheat process (codenamed VANGUARD) can often flag Avast’s anti-exploit shield as a cheating tool and crash itself.

We need to ensure that these processes do not detect each other as threats and crash your League of Legends game.

Avast Shield

One of the simplest and fastest ways around this is to disable the Avast Shield. This will turn off the real-time monitoring aspect of Avast Antivirus, meaning that VANGUARD won’t detect it as a potential threat and crash itself.

This can get you back into the game in a pinch, but for a more permanent solution, keep reading, and we’ll show you how to run both pieces of software simultaneously so you can still keep your computer protected with Avast while you play, but it will no longer interfere with the network.

Avast virus definitions are not updated.

As League of Legends is such a popular game amongst users of Avast when there is a prevalent issue, it usually gets brought up on the Avast forums extremely fast, and hotfixes can often be issued within a matter of hours.

If you are only experiencing this issue, it may be that an update is ready to fix the problem, and your Avast software needs updating.

Flagged as a false positive

Aside from the VANGUARD anti-cheat conflict, this is the second most common cause of Avast blocking League of Legends.

Avast will commonly detect the LoL updater as a virus and move it to the Quarantine Chest. This is an essential file required for League of Legends to run, so we have to restore the files from the Avast Chest and add a new Avast exception so it won’t be blocked again in the future.

How to stop Avast from blocking League of Legends

Now that we know what causes Avast to block LoL, we’re sure you’re keen to get back into the game! Now we’ll walk you through the fixes you can do to regain access to League of Legends and ensure it can’t block it again in the future.

Disable Avast Shield

Avast’s Core Shields is a series of modules that help maintain real-time protection on your machine. 

This is known to conflict with the VANGUARD anti-cheat software used within the League of Legends client, so disabling it will prevent that conflict so the game can launch as usual.

Here’s how to disable Avast Shield:

  1. Open the Avast Antivirus program and navigate to Menu and then Settings.
  2. Under the “Protection” menu, select “Core Shields.”
  3. Right at the top of the page is a simple toggle switch that will turn all Core Shield modules off.

As this will remove Core Shield functionality for the entire computer, we only recommend this as a temporary solution. Keep reading for ways to solve the conflict permanently.

Update Avast virus definitions

When a conflict occurs between Avast and League of Legends, it’s very quick to be brought up on the Avast forum by users. 

Avast will usually react to this new issue quickly and issue a hotfix, so checking if an update is available for Avast and downloading it is an important step.

To update Avast, navigate to the settings menu, click on the General tab, and then find the “Update” tab.

Here you will have two “Check for updates” buttons. The bottom will update the software itself, which is also a good idea, but in this case, we need the top button to check if there are any definition updates and then download and install them automatically.

VANGUARD anti-cheat

A particular situation occurs when Riot’s proprietary anti-cheat framework will detect Avast as a cheating tool and then crash itself, effectively making the game unplayable.

In this scenario, we need to add the League of Legends launcher as an Avast exception within the Avast Antivirus software, so they will ignore each other, allowing you to play the game unhindered.

Follow these steps to add a game file to the whitelist within Avast.

It’s also worth adding the Riot Games folder (located at C:\Riot Games\) as an Antivirus exception as a safety measure to make sure it doesn’t block any additional files.

Run a full system scan

Sometimes the Avast Antivirus program will falsely flag specific files associated with League of Legends and send them to the Virus Chest. Once these files are relocated, they are encrypted and will no longer function, so if they are game-critical files, it will render LoL unplayable.

The first thing we need to do to find out which files Avast believes are malicious is to run a full system scan.

Add virus exceptions from Avast Virus Chest.

Once the full system scan has been performed, we can access the Quarantine virus chest and locate the “LoLPatcherUx.exe.”

Once that file is selected, we can restore it and add the file to the Avast exclusions so it cannot be flagged as malicious again.

Contact support

If none of the above suggestions have worked, the next thing to do is head over to the Avast forums and report the issue there. You will soon find out if others are experiencing a similar problem to you, and Avast will issue an update.

Alternatively, you may find a support staff member who will be able to help you and fix the issue of League of Legends not running.

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