Hi everyone, My MacBook Pro, 2.5GHz Intel Core i7 is running very slow since upgrading to Yosemite with the logging in process being particularly slow. I have tried repairing all of the disc permissions but hasn't made a difference. I also tried to boot from the disc utility but when I restart holding the 'alt' key, only the Macintosh HD drive comes up. Has the process for booting up from Disc Utility changed in Yosemite? Any ideas on how I can speed this back up again as the MacBook was lightening fast before.