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16 Inch MBP 10.15.4 Crashing 2 Displays Clamshell

philosopherdog

philosopherdog

macrumors 6502a
Original poster
Dec 29, 2008
761
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Running the AMD Radeon Pro 5500M 4 GB.

Connecting a Dell U2720A and LG HDR 4K and the Mac crashes when in clamshell mode.

I was connecting them both to usb c.

My current work around is to not put the mac in clamshell.

Anyone have a better solution?
 
Thermally doesn't the Mac pull cool air from the keyboard? Closing it makes total sense that its a thermal issue, better to leave it open for hardware sake, a lot of TDP. Another solution would be to use software to set a manual fan curve for your clamshell load.

Use this. https://crystalidea.com/macs-fan-control

Set a manual fan profile or even run the fan at 100% to see if its a thermal issue or not when closed. Then find the right balance of fan speed to noise that works for you and doesn't crash.... problem solved!
 
Hi thanx for the suggestion. This is a kernel panic. It’s not a thermal issue. Macs are designed to be able to run in clamshell mode. As soon as the Mac is put into clamshell with 2 externals it crashes. Immediately. It is not happening with an older dell running at 30hz for some reason.
 
If you disconnect either one of the displays (only one display connected), does it do the same thing?
 
I'm only experiencing crashes while the Mac is sleeping. I came back from my lunch break this afternoon and the Mac didn't respond, once I opened the lid it started. Doesn't happen all the time, but I'd say it is the fourth time in 2 weeks. My external display is connected via USB-C to Display Port. Never happened without the external display
 
There's a fairly common problem right now related to current Catalina, and kernel panics coming out of Sleep. A temporary fix a lot of people have found (including myself) is turning off any Power Nap features in Energy Saver settings.

forums.macrumors.com

Some Users Experiencing System Crashes on macOS 10.15.4, Especially During Large File Transfers

A sizeable number of Mac users are experiencing occasional system crashes after updating to macOS Catalina version 10.15.4, released a few weeks ago. The crashing issue appears to be most prominent when users attempt to make large file transfers. In a forum post, SoftRAID described the issue...
forums.macrumors.com forums.macrumors.com
 
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I had power nap enabled disable only on battery, now is disabled also for power adapter, hopefully it fix the problem! I read about it and I was sure I disabled the settings, but it was checked... I guess I read it and forgot to uncheck it...
 
philosopherdog said:
it only happens with 2 displays connected in clamshell. As soon as it goes into clamshell it crashes.
Click to expand...

Yes I am having this exact problem. No other workaround I’ve found works. Apple wants me to send it in for a repair after talking with them for over a week.

Also happens running Windows, so I don’t think it’s OSX even.

Interestingly enough, if one of the monitors is in 30hz, it works. But I was only able to get there as a fluke, if I set the monitor to 30 and close, it changes back to 60 and crashes.
 
I have the same issue. Along w/ my 16 inch running Catalina I have a 13 inch running Mojave. This is not an issue for the macbook on Mojave so I think it has to do with Catalina. To be clear this is about running 2 monitors in clamshell mode.

I've changed one of my monitors to 50hz (couldn't do 30 in display pref) and it didn't help.
 
Having this exact problem. Almost same setup - 16in 5500M 8GB, LG 32in 4k + Dell U2720 27 in 4k. Works fine, then as soon as I close to enter clamshell, external monitors go black, and when I open the laptop its display is black too. No report of kernel panic/send report on restart. And definitely not a thermal issue.
 
I'm also having the same problem, MacBook Pro 16" with 5500M 8GB. I also have two Dell U2720 27" monitors and it seems to be related to these monitors. When I plug in to these in clamshell and then attempt to wake the MacBook it crashes, but if it is attached to my old Thunderbolt display (via Thunderbolt 3 adapter) I works fine.

My error seems to be that the windowserver application hasn't sent a report for 120 seconds and then the Mac crashes. Really hope that we can find a solution soon.
 
cfbeggs said:
I'm also having the same problem, MacBook Pro 16" with 5500M 8GB. I also have two Dell U2720 27" monitors and it seems to be related to these monitors. When I plug in to these in clamshell and then attempt to wake the MacBook it crashes, but if it is attached to my old Thunderbolt display (via Thunderbolt 3 adapter) I works fine.

My error seems to be that the windowserver application hasn't sent a report for 120 seconds and then the Mac crashes. Really hope that we can find a solution soon.
Click to expand...

there is a large thread about this common issue with the 16” MBP.
 
Really glad to have found this- after months of thinking it's a software glitch, it turns out to be a hardware issue and still the case in 10.15.7.
I am running a 2019 MBP with two Dell U2715H (or newer) as well as Henge Stone hub and Henge vertical dock. The odd thing is this didn't start happening until a few months ago (coinciding with some software upgrades). I tried bypassing the hub but never thought about testing it outside of clamshell mode as I've alway used my MBPs this way. Also it only happens when the MBP is left dormant (though I've turned off all energy saving/screensaver options to no effect) for any extended time -maybe 10 minute or longe- or when I switch from one dock/workstation to another.

Any resolutions, workarounds, or hacks to resolve this so I can go back to using the docks would be much appreciated.
wdt
 
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