The driver needs to be installed first before the USB DSO can be used. After software installation, plug in the USB DSO, then go to the Device Manager of Windows Control Panel, there should be a new unknown device under "other devices" category, right click it and select "Update Driver Software". Then direct it to the Multi-Instrument software's root directory\Drivers\VTUSB3\32bit or 64bit. This is where the driver is located. Select 32bit or 64bit depending on your version of Windows. Please refer to Section 1.3 of the hardware manual for the above described driver installation procedure.
After the driver has been installed successfully, with the USB DSO connected, start Multi-Instrument, it will run under the licensed mode.