I am having an issue right now and I can't figure it out. About 4 times a day I get the dreaded rainbow spinning pinwheel, but its only on the right half of my upper toolbar. It only started when I upgraded to OS Mountain Lion. The pinwheel starts whenever my mouse moves over the icons that deal with my OS functions (i.e. lock screen, wireless network icon, volume icon, time, etc), but goes away when its on a different type of progam in the toolbar (i.e. magicmouse, plex, etc.). Its an early 2011 macbook pro and I have enough RAM and fast enough processor to handle mountain lion, but I can't figure out why it keeps doing this. Anyone have a clue?