[Client] Client won't launch properly.

I launched the game and the logo appeared in the middle of my screen and then will disappear. Nothing will happen afterwards, and no corresponding tasks will pop up in Task Manager, in the Processes section. When I go to try and launch it again a black box will take up the top left portion of my screen and it will stay black. I close the program in Task Manager because it won't close from the Windows Explorer bar. Trying to launch it again will repeat the same process.

I was able to solve this by going into the Details section of Task Manager and ending all tasks corresponding to LoL. After that, the game launched as intended and I can close the game without running into the same issue as before. I'm unaware as to how to replicate the bug.