External Displays won't come back on

All kinds of display issues on my Macbook 16" with Catalina 10.15.3

I connect to a Dell 4k monitor via USB-C > DP cable. If it's working then it works... if not (about 80% of the time) then it will randomly turn off and on as if the monitor is being plugged back in. Sometimes I can see the shut-downs coming by some on screen corruption (static or horizontal lines flashing). I can't figure out what conditions lead to more stability... I've tried all sorts. All I know is that once it's working fine it usually stays fine until sleep/restart then I'm taking my chances all over again. VERY FRUSTRATING. Catalina has been nothing but a headache for me.

Mine is exactly opposite... when I switch to the Right site flashing stops (after waking up) but when on the left side only a reboot seems to help (other than unplugging the external display ... which is HDMI)

Oddly, my setup (LG 27" and 16" MBP) has not had the black external display bug for over a month now. Leaving on constantly and allowing everything to go to sleep. I do experience a drastic color shift on the external every so often (colors are over-staturated on wake). I am able to rectify by closing laptop lid and opening. Running 10.15.3.

Same issues on my 2019 MacBook Pro as stated by all the other posters. Only way to solve the issue for me is to shut down and restart. Occasionally, I have to force a restart by holding down the power button as well. A shut down/restart via the Apple icon doesn't always work; the computer will sit stuck at the screen that shows the desktop image but no menus, etc. Can hang like that for 20-30 minutes. Not sure if that is related or something different.

I just upgraded. I will report tomorrow (because computer always crashes overnight whilst asleep). But after several hours has been stable. (That is good sign -- about 80% of the time left for over an hour asleep it crashes).

Well....same here, the external monitors are now working but if I let it sleep for a few hours the MacBook crashed every time, here are the logs when it crashed with all my apps running:

(See "logs" at the bottom of the message)

Here are the logs after I it crashed with all apps closed (I closed all apps in hopes it was a glitch with an app and one of the apps was causing it to crash, but no such luck....again the logs with all apps closed:

(See "logs" at the bottom of the message)

APPLE PLEASE HELP❗️

This is craziness that we now have to disable the sleep feature yet again, probably for another 3-4 months before

10.15.5 comes out . Hopefully after 10.15.5 this will all be over and this thread can be done and RESOLVED!

If anyone has a fix for keeping sleep enabled and to stop these crashes please post. I have not even tested with sleep off yet, just hoping disabling sleep will stop the crashing!

So far so good for me on 10.15.4... I left it overnight. Woke up fine this morning. I was actually not experiencing the issue as of late though. It was waking from sleep fine. The only issue I did notice is a drastic color shift on the external display on wake at times. It was fixed by closing laptop lid and reopening.

So far so good for me on 10.15.4 as well. Upgrade went smoothly for me. No panics or what not. I'm holding out hope that they did get the fix in even though it wasn't in any release notes that I've found. I asked for verification to their social media team and they suggested that a sr. advisor call me again. I'm sure that is a great use of time to have the verification. But oh well. Not going to argue that. Hopefully all is well with this particular issue and that if there are still outstanding issues that they get cleared up fast.

Well I observe a new behaviour (since 10.15.4):

When my computer goes to sleep (all the recommended settings applied) and wakes up, my externe LG screen (connected via a CalDigit hub) stays black.

When opening the Display settings on MacOS, go to positioning and select the "sync displays" options, it comes on. When deselecting the "sync displays" option again, it works as it was before going to sleep.

Getting weirder and weirder. Maybe Apple employees do not work on MBP16" with an external display or they would escalate internally?

Same here.

After some hours it seems that the external screen goes into a deep sleep.

My technique is to login via MBP's screen then use fn+F1/F2 on my external keyboard in order to change brightness.

External screen is the master screen.

I am back in business.

MBP 16" ($$$$$)

Thunderbolt Screen ($$$)

MacOS 10.15.3

I had the exact same kernel panic last night. [OS 10.15.4]

Settings->Energy Saver was all Defaults.

The crash report was the same as above, and my Console system log at the time of crash was busy generating the following DumpGPURestart messages for about 35 minutes.

------

Apr 1 01:31:10 --- last message repeated 1 time ---

Apr 1 01:31:10 SR-MBP-16 com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.pid.activateSettings.18510): Failed to bootstrap path: path = /System/Library/PrivateFrameworks/SystemAdministration.framework/Versions/A/Resources/activateSettings, error = 2: No such file or directory

Apr 1 02:06:15 SR-MBP-16 syslogd[109]: ASL Sender Statistics

Apr 1 02:06:18 SR-MBP-16 com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.pid.activateSettings.18520): Failed to bootstrap path: path = /System/Library/PrivateFrameworks/SystemAdministration.framework/Versions/A/Resources/activateSettings, error = 2: No such file or directory

Apr 1 02:06:57 SR-MBP-16 com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.pid.backupd.18524): Failed to bootstrap path: path = /System/Library/CoreServices/backupd.bundle/Contents/Resources/backupd, error = 2: No such file or directory

Apr 1 02:07:57 SR-MBP-16 com.apple.xpc.launchd[1] (com.apple.DumpGPURestart): Service only ran for 5 seconds. Pushing respawn out by 5 seconds.

.....

(hundreds more lines like above, excised due to text limit)

.....

Apr 1 02:41:15 SR-MBP-16 com.apple.xpc.launchd[1] (com.apple.DumpGPURestart): Service only ran for 2 seconds. Pushing respawn out by 8 seconds.

I have been using my Macbook 2018 model perfectly without a single issue with the LG 5K display, but this week I upgraded to a new 2019 2.4 GHz 8-Core Intel Core i9 -

AMD Radeon Pro 5500M 8 GB

Intel UHD Graphics 630 1536 MB

And now this 5K LG screen is causing the New Macbook to crash every time i leave my desk. I come back and have to unplug the screen re-boot the mac and start again. I'm going to my old mac or sending this new one straight back if they cant fix it.

Well looks like 10.15.5 update came out today....nothing mentioned about monitor issues in update notes, but one can hope right, especially when I paid $6k for this 16" MacBook.

If you update to 10.15.5 please let all of us know if update makes any difference for external monitors or do we still need to keep sleep off when plugged into an outlet?

Thanks for your replies in advance guys, hopefully one of these days Apple will bless us with a fix to external monitor issue so we can use the sleep function even when plugged in on a $6,000 laptop (UREAL, sorry don't mean to venting a little, but this is really getting old, just release an update or at the very least acknowledge the issue officially). We are loyal customers and deserve better (in my opinion), I have NEVER posted o a forum until this issue.

C'mon Apple, please please pretty please guys resolve this monitor nonsense❗️

Same problem for me. Got my MBP16 a few weeks ago. Lower-end 5300M-card. External LG 27-screen (U2717D). Had this problem since day one. I'm on Catalina 10.15.5. Mac crashes when falling asleep with an external monitor connected.

To get the screen working after a sleep-crash I have to hold the power-button 10sec to do a hard power-off. But in about 25% of the cases I also need to do a SMC-reset to get my external keyboard to work again (since the USB-C-port refuses to acknowledge my keyboard, and an SMC-reset is the only way I've found to get it to accept it again).

So.

Last nigt I re-installed Catalina (clean install, even wiped the disk first).

External display connected, lid closed, external keyboard plugged in. I was waiting for it to fall asleep (I have it set to 15min).

Sure enough, coming back an hour later it couldn't wake up.

External screen black.

When I open the lid, the internal screen is black.

I'm sending mine to a repair shop, I'm still on AppleCare or whatever, it's been less than three months.

But jeez.

The gpu on these new machines cannot support external monitors and graphics intensive software at the same time. I have been going through 4 months of support to resolve this issue and the engineers are at a loss.

I hope they aren’t trying to force our hands into purchasing eGPUs as that is a new item on the market. My 2014 iMac had three monitors hooked up to it at the same time and these new machines choke with one or two while using Adobe software. At this point just having the external monitor plugged in causes a problem. I smell a recall coming.