External display not working after Catalina update
Hello,
I have a 2013 MacBook Air and use an LG external monitor connected via the Thunderbolt port. After the upgrade to Catalina v.10.15 the external monitor has stopped working. I've tried everything suggested online, disconnecting everything, restarting, checking for updates, checking Display preferences. When I first plug in the external monitor after a restart, both displays flicker non-stop, the Mac screen flickers between the desktop and the login screen. If disconnected, the Mac then ignores the external monitor and the monitor goes to sleep, without it ever being detected. Please can someone help?
Thank you
MacBook Air 13", macOS 10.15