Occasionally, when I go to turn on Multi-Model Buffering, I get stuck with my game loading like this.
This often has mixed results, the most common being that everything becomes unclickable (and thus causing me to have to manually close the Client). Restarting the Client and attempting it again usually results in the same thing, but after awhile the MMB finally loads properly.
Recently, I attempted again and found the same thing occuring, but I could still click on the window, prompting me to deactivate MMB which returned everything to normal. Attempting it again yielded the same results until, like before, the MMB finally loaded properly.