I seem to recall that the very first MS Bluetooth mouse came out before BT HID was really finalized (or something like that), and it basically would only work with the BT usb transceiver that it came with. I think also the BT transceiver did not support pairing with other BT devices.. So it said 'Bluetooth' but basically wasn't compatible with anything else bluetooth. I remember buying it years ago from Best Buy and returning it within a day... (I was looking for a mouse that would work with my laptop's builtin BT transceiver)