An unknown DirectX error has occured and League of Legends cannot start. Please make sure your video card is using the latest video drivers from the manufacturer.
It's a really common error and causes many players to lose LP since it takes a while to fix.
If you are not interested in the trial and error process, fix is below.
I have had this error 3 times now. First time I tried relogging, restarting computer, and finally totally uninstalling and reinstalling. As you might expect this cost me a lot of time.
The 2nd time I had this bug I looked it up. I found this post:
In this post they said I had to remove files from League and repair via the client. This worked, for then.
Now just recently I got this error again. I was not in the mood to go through the files removing process again so I looked for some other solution:
Using these sites:
Usually such error messages are because of DirectX.
a. Click on Start > Run.
b. Type regedit and press enter.
c. Go to the following location: HKEY_LOCAL_MACHINE\Software\Microsoft\DirectX
d. Right-click on DirectX and select Delete.
e. Restart the computer.
f. Download and install latest DirectX.
I ran into the problem that after removing these files my Windows 10 said my DirectX was already up to date and installed.
If this isn't the case (might happen on older Windows versions) you can download DirectX and it will automaticly check if you need it or not.
Download DirectX from here:
After this, and restarting my computer (not sure if necessary) the game worked again.
It's a lot quicker fix, since the only thing I actually did that affected anything is removed the DirectX files from regedit.
Hope this helps some people