I have a second display (Dell ST2410) connected to my 27" iMac via a Thunderbolt 3 to HDMI cable. This was working fine in macOS 10.14.x, but since updating to Catalina it's only showing a blue screen. If I disconnect and reconnect the cable I do see my desktop background display quickly before the screen goes blue. If I open Settings and go to Display, I can see that the monitor is being detected as well. Does anyone have any ideas on how I can correct this?
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Second display only showing blue screen
- Thread starter bisk
- Start date
- Sort by reaction score