Can I use HDMI for audio only without video? When I connect an HDMI display to my computer, it uses it as a display. I can't figure out how to use the HDMI cable for audio only and only use my laptop monitor. Is this possible?
If all you want is to have your desktop confined to your computer's screen, go to System Preferences > Displays > Arrangement, and check Mirror Displays. That'll make it so that your HDMI display only acts as a mirror of the desktop you already have, rather than an extension of it.