Dual Screen Mode Set up

Anita

I am struggling with a similar problem. I have a Mac Pro (2009) connected to a Samsung large display with a VGA cable. I gently bought a Jetson Xavier board which has several CPUs on it and connected wit with an HDMI cable to the same display. How do I get into dual mode display? I went to system preferences> display but there is no Arrangement tab. I already unplugged the HMI cable and restarted my Mac but Mac OS does not seem to recognize the HDMI connection. How to switch from VGA to HDMI and display the results in two different windows on a single display?

Thanks for any help you can provide

Is your external display recognized by the Mac?

i think your HDMI cable or VGA cable is not connected properly to the monitor, otherwise MacOs recognise the screen instantly as soon as you connect.