My League client is just a black rectangle on my screen

Hey tin this was posted about a year ago but if you should run into this problem again here is the fix.

1. Open task manager (ctrl + shift + esc)
2. scroll down the manager and look for anything league related
3. if you find anything league related right click on it and select end task.

do this until you see no more league in the task manager. After that exit task manager and open league.