Im going to assume its Yosemite, as this is a recent problem 2012 mac mini Logitech M510 with the little unifying receiver Happens when plugged into Amazon USB 3.0 hub and directly to the mac mini Ive suddenly began experiencing connectivity issues with the mouse which is less than 3 months old. It will stop tracking all together and clicks (right and left) will continue to work. This seems to be temporarily fixed with a reboot of the mouse and unplugging and plugging back in the receiver. Quite frustrating while playing RPGs.. Anyone experiencing similar issues with similar peripherals? If not, I may have to return this mouse.