I upgraded to 8.1 last night and my shutdowns were taking 5 minutes or more. I associated with the upgrade, but nothing I did would fix it. Finally I did the only thing I hadn't tried, turning off the bluetooth (I had turned it on after the upgrade), and my shutdowns and startups started taking 20 seconds. Before, it would get to a black screen fairly quickly, but the power button would stay lit up for 5 minutes after that. Now from the moment I hit shut down to when the light goes out is 20 seconds or less. That doesn't make this okay because I shouldn't have to switch my bluetooth off before shutting down each time, but at least my new laptop is fast again.