I'm going through the same problem. When I first connected I got a message that the drivers were not found and it wouldn't connect. Moved to a different port, same thing. Uninstalled and reinstalled Polar Flow, same problem. Called Polar tech support and went through the same gyrations, same result. Finally after reinstalling and rebooting the computer with the V650 attached and turned on while rebooting I got it to work...once. Next time I tried same problem. You'd think a company the size of Polar could figure out how to get a simple usb connection to work, but apparently not. I also have a Polar V800 and M400 and they both work flawlessly, so I'm sure it's not my computer. If anyone finds a solution please post. thanks.