Ran into this problem firing up Weatherlink 6.0.3 for a new Vantage Pro 2 on a Windows 10 machine. In Weatherlink, Set Up > Communications Port, the pre-selected option was Serial. I changed this to USB since the connection from the console to the computer was of course a USB cable. But the software did not find the station. The Owners Manual accompanying the Weatherlink software (mercifully Davis still provides hard copy manuals with their products) addresses this specific problem on p 23. It may not have done so in earlier versions of the software or earlier issues of the 6.0.3 software. Anyway, in the manual current as of this writing, if you have the problem that Weatherlink can't find the Vantage Pro 2 station with the Communication Port in Weatherlink Set Up set to the USB option, Davis advises that you call them. I first contacted a Davis product support location, apparently not in California, and they immediately referred me to actual Davis in California, currently 510-732-9229. Three mins on hold; pretty good. There a tech meister named Bruce very ably led me flow-chart-like through a number of checks and tests on settings until, having reset the Communications Port in Weatherlink back to "Serial" and the default COM3 port in Weatherlink to COM8, we reset the default com port in Windows Device Manager > Ports (Com and LPT) > Silicon Labs CP210x USB to UART Bridge (COM3) from (COM3) to (COM8). This worked. Don't know if your circumstances as of this writing would be the same so the indispensable thing is to call Davis. They fixed me right up in about 8 minutes.