For a lot of the time the scrolling works, but sometimes for around half an hour to an hour at a time it doesn't work at all. Normally when scrolling with the mouse when it works you can ever so slightly feel the vibration of the ball. When it doesn't work I wont be able to scroll in a direction (for example, I can scroll up but not down). When I move the ball in this direction it wont scroll in, the ball it rolls completely smooth. I attempted to take it back to BestBuy however they needed to see it broken. The person I spoke to scrolled the ball on the mouse for a good ten minutes and it finally started working. Then I was told that since it was working I wasn't allowed to get a replacement...I don't want to have to spin the scroll ball for ten minutes every 4 hours to get scrolling capability back.