Mac - can't start a game

An update was applied today when I started the client. When a game is starting, it would either show black screen or only 1/4 of the image and it wouldn't go any further. after restarting many times, the results were still the same. When it showed 1/4 of loading image, I saw the screen said "beta ......". I wonder why on earth would a company release a beta version? I wonderrrrrr