Level 1

118 points

External Displays won't come back on

I have a new 2019 16" MBP (2.3GHz 8 core with Radeon Pro 5500) MacOS 10.15.1 with the supplemental update installed.

If I attached external displays they work fine. BUT if the computer turns off the displays (e.g. if I lock the screen or walk away for a few minutes) then when I come back and try to use the machine again, then the screens flash intermittently (across all the screens, the inbuilt display and the external monitors) and continuously. Then the MacBook's fans start spinning like a jet taking off. It's like the display driver is continually crashing.

If I unplug the external displays then the internal display comes back to life and I can use the mac again. BUT from that point on I can't plug the external monitors in again or I get the same problem. To be able to use external monitors again I have to reboot the machine.

The only workaround I've found is to set the screens to never go to sleep.

This is VERY frustrating!

Any ideas?

[Re-Titled by Moderator]

MacBook Pro 16", macOS 10.15

Posted on Dec 9, 2019 10:13 PM

Top-ranking reply

GreyFoxTheElder

Level 1

4 points

Posted on May 5, 2020 12:22 PM

Please see my earlier response. The new 16 inch Macbook requires more power than the LG display can supply. I solved this by keeping the 96 Watt power adapter that comes with the Macbook plugged in along with the USB-C cable from the LG 5K display. I have not had a single problem since.

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143 replies

stecas

Level 1

4 points

Mar 23, 2020 3:06 PM in response to gresmi

Exactly the same. Happens me every day. Extremely frustrating.

MacOS 10.15.3m

MacBook 16"

stecas

Level 1

4 points

Mar 23, 2020 3:11 PM in response to GolpherZX

I cross my fingers. This is very irritating indeed.

LATol

Level 1

4 points

Mar 23, 2020 5:13 PM in response to raydmak

This has been my solution too! Even shared with my IT team.

So far so good!

stecas

Level 1

4 points

Mar 24, 2020 8:32 AM in response to raydmak

Thanks Raydmak,

Works like a charm.

MacOS 10.15.3

MBP 16"

Thunderbolt Screen

raydmak

Level 1

4 points

Mar 24, 2020 10:28 AM in response to stecas

YAY! 😃

I hope they fix this soon! It's a total pain 😖

dima929

Level 1

5 points

Mar 24, 2020 3:12 PM in response to Tom DePrenda

Has anyone updated to 10.15.4 yet....if so can anyone please confirm if this resolved the issue with external displays not waking up?

Thanks guys!

Marko S

Level 1

4 points

Mar 25, 2020 10:14 AM in response to Tom DePrenda

The LG 5k bug they call out in the notes definitely doesn’t describe the bug i’ve been seeing. The only similarity is that it’s display and sleep related.

claporte

Level 1

26 points

Mar 26, 2020 6:29 PM in response to El_Faro

Alas, while both of my external monitors have come on when successfully waking from sleep today after 10.15.4 update, I also experienced a crash when attempting to wake.

crobiou

Level 1

4 points

Mar 30, 2020 2:07 PM in response to gresmi

Jesus christ. Same. Have you found a solution? This is infuriating.

ncor

Level 1

4 points

Apr 16, 2020 5:26 PM in response to gresmi

Same issue here. Super frustrating as this machine cost a ridiculous amount

Apr 21, 2020 1:26 PM in response to gresmi

Same issue here too. I am running a Cisco DX90 as my second screen. It works for my 2018 MB Pro no issues but the new one causes a crash.

May 27, 2020 1:12 PM in response to dima929

I updated last night and left my 16” MBP connected to my monitor overnight. MBP crashed while I was sleeping. So, no fixes in this update.

stecas

Level 1

4 points

May 27, 2020 1:49 PM in response to mlippmann

I wonder if Apple reads this thread?

Hope someone has reported this problem to an Apple Service Center.

Jun 8, 2020 5:06 AM in response to ThAune

Amazing, 8 pages deep 6 months, and still no fix from Apple, that a quality product right there?

ThAune

Level 1

8 points

Jun 12, 2020 12:24 AM in response to El_Faro

That work-around does not work on my Mac. I often put my mac into sleep, and go to meetings. When i come back, it's crashed. Testing to have the lid open for today..

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External Displays won't come back on