There are also some cases where the external display just blinks randomly when connected to a Mac running macOS Catalina. Other users, on the other hand, got a No Signal error message instead of the black screen. The display just turns black (or dark green in some cases) and eventually shuts down. Several users reported getting a black screen after installing the new version of macOS, even with the monitor still turned on. Some Mac models, such as the Mac mini, also rely on HDMI to connect the computer to the display.īut with the release of macOS Catalina, a lot of Mac users using HDMI connection reported encountering various problems after the upgrade. Whether you want to use a second screen or you want to export full audio and video display on your TV, connecting your devices is a lot easier with HDMI. You can connect the HDMI cable to the HDMI port on your Mac to a second monitor or TV. One of the ways to connect your Mac to an external display is by using a High-Definition Multimedia Interface or HDMI cable.
