League of Legends error code 0U explained

It's like the client doesn't even know how to function anymore.

Yuumi Bio
Screengrab via League of Legends

Getting into a match of League of Legends can be a challenging task sometimes. Unlike other games where the lobby is buried into the game itself, League has a separate client interface that allows players to interact with their friends without actually launching the full game.

Though this is convenient with almost anyone with mid-to-low tier PCs, tiny bugs that affect the Riot client can prevent players from joining matches even if the servers are functioning properly. The origins of error code 0U are unclear, but it’s been affecting users from all around the world for a while. 

Riot was quick to acknowledge the issue and confirmed that it’s working on a fix, but that doesn’t mean that you have to wait with your hands tied until the developer finds a permanent solution to the problem.

There are a couple of band-aid fixes you can try out, but none of them can fix the error for good. The chances of error 0U reappearing are still quite high and you’ll need to wait for Riot to patch out this minor annoyance.

How to fix League Error Code 0U

Community managers or Riot members haven’t disclosed an official solution method that players can try, but community members that reached out to Riot’s support line were advised to run the Hextech Repair Tool.

Hextech Repair Tool is a utility program developed by Riot that automatically runs a troubleshooting session. The Hextech Repair Tool has multiple tools at its disposal to detect corrupt game files and can reinstall a patch or the game itself from scratch.

Try adding League as a Firewall exception and also repatching the game. If these two options don’t seem to fix your problem, we recommend reinstalling League through the Hextech Repair Tool. The Tool also collects all of your League logs that you can send to Riot support to help them pinpoint the root of this issue.

The above method isn’t guaranteed to work for everyone, though. Even players who’ve successfully bypassed the error by reinstalling were greeted with it once again after some time.

Keep an eye on the support page to track Riot’s progress regarding the error. If you’re determined to play a game of League before bed, you can continue to try your luck by continuously trying to log in after receiving the error.