After pairing fails, right-click on the device and look for the field 'address'. Press the red sync button on the back of the Wii remote. To get the Bluetooth passcode you must find the Bluetooth address of the Wii remote. I love the new resize function replacing the S/M/L sizes, giving the user freedom to use the emulator in the most comfortable way possible. Since the El Capitan update, Bluetooth pairing requires a passcode. We are happy to see that it didn’t take longer for him to come up with a new version, bringing back the full-screen mode and other goodies: The explanation he gave me was that the API used to achieve that mode was deprecated and wouldn’t work anymore in recent versions of MacOS so he decided to turn the feature off while he was working to update it using the current MacOS API. A few weeks back, Gerard had released another update for the emulator, but at that time he had to disable the full-screen mode.
Even after uncountable years out there, Virtual II developer, Gerard Putter keeps working on it and make it even better.