I just updated to macOS 10.15. My external monitor stops working. It will show image for five seconds, then it turns to a blue screen. I tried to reset SMC and NVRAM, both don’t work. Does anyone know a fix?
MacBook Pro with Touch Bar
I tried SMC, it doesn't work. I didn't try using a second account. And change the resolution made no difference.
However, my monitor indeed work under safe mode. But as soon as I am back to normal mode, the monitor won't work again.
Right now, I am using a USB-C to DisplayPort cable, works fine.
Same problem here with the same adapter (DELL USB-C to HDMI 2.0), and recent 10.15.2 still hasn't addressed this issue.
Googled all around the internet and found no fix as yet. Haven't been able to connect to my TV to watch a movie for two months now, which is really frustrating...
Same for me. It worked perfectly fine before update to Catalina. HooToo dongle (USB-C -> HDMI) connecting to Sony TV. It's ok for 5 secs and then goes blue.
I guess there is still no fix to this after almost a month after the last post?
On a separate note, I tried resetting SMC and NVRAM but is there a way to check if they actually were performed successfully?
I’m using the OWC usb-c dock too. Have been experiencing the same problem with any external display. The problem seemed sorta fixed the other day when I updated to 10.15.3 but it was flashing blue for about 15 mins before it settled. Now it’s back to a solid blue. Did the SMC/PRAM reset and nothing. This is really irritating and something that old Apple’s QA team would never let last this long.
I'm really starting to rethink Mac computers for the first time in 15 years. I need to use this computer at my desk! This is affecting my ability to work now!
After installing Mac Os Catalina 10.5 I have the same problem connecting projector Epson. It shows 5 seconds normal picture and then it turns to blue screen. External monitor Samsung works fine.
Thanks for a feedback lucky13820.
No, it didn't work. I am using HDMI to connect to my monitor. I don't think it has anything to do with Displayport.
Bump. Waited to upgrade until 10.15.1 dropped then updated. When I connect to my work's TVs to show a presentation, it shows for 10-15 seconds, then drops to blue. Macbook Pro 15" 2018.
I have the freaking same problem. I just bought my Moshi Multiport-adapter for my MacBook Air 2018 only to find out that it has this problem!!!
Fix this Apple!!!
Same here I just got a new MacBook Pro 16" and when I plug it in to a display it works for 5 secs and then turns blue on the display screen. Very painful.
Does booting into Safe mode make any difference? Does using a second account make any difference?
Does changing the resolution make any difference (do an Option-click on the "Scaled" item in the System Preferences "Displays" item to see all the possible choices and try them out).
Have you tried an SMC reset?
Good luck...
My external monitor shows a blue screen after update to 10.15
