Bluetooth is not perfect and other things in the computer/environment can affect its reception. On my old laptop there is a small hole in the bluetooth reception exactly in the ideal spot for me to keep my trackball, took awhile to figure it out and I only have to move the track ball a half inch in any direction to get it out of that void but it never seems to fail that either laptop or trackball will eventually move and it will lose the connection. So I just use the dongle with that laptop and I am glad it came with the dongle.