After inserted the USB receiver, there is a circling icon in the lower-right corner of the window and it starts to install device drivers. Some users may preset “Windows Update” priority search to install drive. If yes, please skip the step of “Windows Update”. Three options will be (√) automatically before installed successful. Calibration needs be done with “ON” mode. And user can choose “ON” or “Eco”, and make the setting base on personal preference.