I have a MX1000 and am running 10.4.3 at the moment. I also have a MX500 wired mouse which works perfect, very smooth. When I use the MX1000, the mouse pointer is quite shaky when I slowly move it across my mouse pad in a straight line. The pointer shakes around a little on the screen, about the line I am moving the pointer through. I have tried resetting both the mouse itself and the charging base, no effect. I have used it both without installing Logitech Control Center and with, same problem both ways. Anybody else ever have this problem or know what I can do to fix it? FYI I have used my MX1000 with a PC no problem in the past.