I have a MBA with OSX Yosemite and it has been running nice and smoothly for a couple of years - no issues. Somehow, I have inadvertently caused my Safari to open with a million tabs trying to load a whole bunch of sites but this creates the lovely colorful pinwheel to appear indefinitely. I have tried completely rebooting and then only bringing up Safari and left it sitting overnight to see if it would finally level out. No such luck. I can't think of anything else to do to close all of these tabs to start a fresh Safari session. Ideas?