Unity Freezes when Loading GUI

This might be a problem just for me because nobody else asked this. Whenever Unity loads a GUI, the editor/application freezes. This only happens on my Mac. It doesn't occur on any web player projects, but only editor/standalone ones. If I were to add a GUI button to my game and play it, it freezes for about a minute and then plays. However, it stops freezing after the first load. So if I opened up Unity and started my game, it'll freeze but if I stop and start it again, it doesn't! Any reason why?