MacBook Pro 16" Kernal Panic During Restart when Plugged into Dual Monitors

I have the same issue, kernel panic when plugged into external monitor. It has happened to me twice in the last three days I've had the computer (16' MBP with i9 9880H and Radeon Pro 5500M 4GB). But I have a different error message:

I let Memtest run for 1 pass, it took about 40 minutes. I created a bootable USB and booted from it to run the Memtest utility. This person has the exact same error message https://discussions.apple.com/thread/250917084 on the 16' MBP.

As you can see here: https://discussions.apple.com/thread/250878229?answerId=252321460022 thousand of users are having issues with the MacBook Pro 16-inch, overheating, kernel panics, external monitor not working, it seems to be a software/driver issue but it's been 3 months and 2 MacOS updates already and the problem is still there.

Hi Christian,

I'm in a very similar situation. Slightly lesser spec on the MBP and two LG Ultrawide 5K Thunderbolt displays; same behaviour in regards to kernal panics.

I also have two other problems;

1. the MBP sometimes doesn't wake up if it is connected to the external display. Opening the lid will either wake up the machine or cause a kernal panic (Fans and restart as you describe)
2. The MBP doesn't detect the screens adequate resolution when waking up

Does this happen to you as well ?

In my case, I found that this is caused (or at least aggravated) by parallels.

I finally have mine fixed... Here's my setup:

• 16" MBP - pretty much loaded
• 1 x 5k 27" LG monitor (new as of January)
• 1 x 45 21.5" LG Monitor (older model from a couple of years ago)

Whenever my MBP went to sleep, the MBP crashed... Not every time, but prolly 70% of the time.

I downloaded "LG Screen Manager" and updated the firmware on both monitors. It's been one week now and I haven't had a crash at all. Occasionally, whenever the MBP wakes from sleep one or the other monitors doesn't turn on, but this is fixed by putting it back to sleep again and then immediately waking it.

Hope this helps at least one of you.

Had the same problem. It's now solved.

Status here

My GPU Panic sleep problem is still solved. I have since installed my video-rendering tools, my developer tools, all my other stuff.

My energy saving stuff is back to normal (standard settings)

Having it gooing to sleep on power, on batteries, forced it to run out of batteries. Did intense GPU-use. Still no problems.

Running 10.15.4

Solution for me was

My brand new macbook pro 16 (Shipped 2. april 2020) also restarted (crashed) over nigth - actually it crashed (Kernel Panic GPU) everytime it went to sleep mode. I had nothing installed except default OSX with updates.

Solution details

1. Reset: Pram & NVRAM (still crashed)
2. Reset: SMC (still crashed)
3. Internet Recovery Command+Option+R (when booting) (Crashed under installation, but continued afterwards)
4. Disabled "Prevent computer from sleeping automatically when the display is off." & "PowerNap.." in Energy Saver settings (Problems disappeared)
5. Two days later I enabled "Prevent computer from sleeping...." and "Powernap..." again (Still no problems)

I don't know if step 1-3 is necessary, but I think so.

So a macbook pro 16 that I almost returned, is now working perfectly - and I'm very happy:-)

as the kernel panic does not happen always i have studied the Kernel log and it seems to me it happens always when after waking up from sleep the system makes a call to a specific core of the cpu, it really seems a software bug.

after that i have decided to do proceed as follow in order to avoid the faulty call to the cpu core

• Disabled Powernap
• Enabled prevent computer to sleep if display is off
• disabled put hard disk to sleep
• disabled SIP
• disabled out turn on at lead open (via terminal)

not sure what did the trick, but

now with 2 monitors connected

no more kernel panic, more than a month now

hope this will help you too guys

I found the solution for my similar problems (about 10) Kernel Panic restarts a day) berried in the forums:

Disable Handoff in system preferences -> general -> handoff

I went ahead and turned off handoff and have not had a single crash in 3 days

Thanks

see attached file

Sometimes problems like this have already been seen and solved. Be sure to apply the latest MacOS updates so that any such changes are already incorporated into your system.

That is likely to be the first thing an Apple support specialist will ask for -- they do not want to debug a problem that has already been solved.

Update: Just as a further thought and test...I separated the monitors from a single thunderbolt bus to two separate busses(?), my Mac Pro 2013 has three thunderbolt/video busses.

Nothing special at all in the shutdowns, shutdown regardless of anything else seems to work fine.

FWIW.

No way am I doing a full system reinstall that may not work for such a simple workaround.

EverythingTec wrote:

I have the same issue, kernel panic when plugged into external monitor. It has happened to me twice in the last three days I've had the computer (16' MBP with i9 9880H and Radeon Pro 5500M 4GB). But I have a different error message:

<Error Message.log>

That error message show a RAM Memory error, detected by some of the most thoroughly tested parts of MacOS that have to do with memory allocation and queues.

The hexadecimal pattern expected deadbeefdeadbeef a "too cute" pattern used by programmers for empty memory, but instead found deadbeeedeadbeef, a single bit error.

Normally, I would say you have an obvious RAM problem, However, you have made your situation impossible to debug because you have loaded TWO Hypervisor/Virtualisors, both VirtualBox and Parallels. You must choose one or the other, not Both, if you want relaible operation of your Mac.

Thanks for looking into my issue! I have had the same error message twice in the past week (deadbeee instead of deadbeef). The first time I had the issue, I did not have any hypervisors installed on my system. Both cases happended exactly when I plug in my Dell U3415W monitor with a USB-C to DisplayPort connector. I think the chances of hardware failure causing the same bit flip at the same offset is very small. I have also run the Apple Hardware Test and Memtest86, both passed with no errors. I think it is very likely a driver related bug.

I think you have a RAM memory error.

How long did you let Memtest run? was this standalone or under MacOS?

Drivers have no business accessing memory allocation queues. They should be in a separate protected space.

Yes; it solves none of it.

The only thing that helps is disabling sleep mode.

After the BS i had to endure with last years model, I don't think that Apple gives a ****. After all, it's only "a small percentage of users" who are experiencing these problems.

"The only thing that helps is disabling sleep mode. "

Actually, as of 10.15.3 , it doesn't. The update actually made it worse.

Just got two kernel panics in one hour. What a joke. The thing is more stable running windows than Mac OS

If anybody is starting class action, i'm certainly in.