When I go into System Preferences->General, there is no option to select "allow handoff". I have been using all of the Yosemite public betas, and I even downloaded the official release today and installed that. Still no luck. Phone calls work to my macbook air, but I can't get any icons to show up on the left hand side of my dock on the air, nor can I get any icons to show up on the lock screen on my iPhone. I have checked all the steps. I have signed out of and back into iCloud on both my Macbook Air and my iPhone 6. I have bluetooth and wifi turned on and connected to the same network on both devices. The bluetooth on my Air is supposed to be compatible (0x6), according to other forums I've read. Help?