Code to fix: WindowServer[250]: _CGXGLDisplayContextForDisplayDevice: No matching context for device (0x7fcfcaf18220) - disabling OpenGL
From the original answer:

Type the following into your terminal: sudo nano /etc/asl.conf.
Now, use the arrow key to go to the bottom. When you are at the bottom, paste it the following:

? [= Sender WindowServer] [= Level Warning] [A= Message _CGXGLDisplayContextForDisplayDevice] claim only


(There is nothing special, just command+v).

Now, hit control+x and hit y. Now, type sudo kill -hup syslog.

Sudo means super user grant, so you are giving the command access to all of your machine.