Edited by williamgomes, 30 July 2018 - 09:29 AM.
macOS Sierra external display resolution
Posted 29 July 2018 - 10:20 PM
Posted 30 July 2018 - 06:38 AM
Check that the external display installed is still the same. When a device is not in the macOS plug n play setup list the default will be used.
You will need a manufacturer installation program for the display.