Dual Monitor Setup crashing Monterey

I had the same issue with my Intel i7 chip Macbook Pro

The problem has been solved by lower the Built-in retina display Refresh Rate to 48 Hertz when connect with dual monitors.

I decided to test this and indeed, lowering the main screen's refresh rate from 60hz to 48hz makes this problem go away. I am retrying with 50hz to see where the breaking point is.

Solved!

I went into the Displays setting in Control Panel and changed my monitor refresh rates from 60Hz to 59.94Hz. After that, I have had no more issues.

adapters only, no Docks?

Kernel Panic Reports are stored at:

/Library/Logs/DiagnosticReports

If you copy and paste that string into:

Finder > Go menu > Go to Folder

it will take you to where those reports are stored.

They are named with Date&Time and start or end in ‘panic’

If you find one, please post the entire report here, by using the “additional text” Icon in the reply footer (looks like a paper with writing).

Please don’t post more about 20 lines of any other types of reports — they are interminable, and any information useful for this purpose is on the first screenful.

There are three quick take-aways from any panic report.

1) The panic-reason,

2) the extensions present at the "scene of the crime", and

3) the BSD process in which the problem occurred.

One more item that is important is the names of any third-party Extensions you have added. They are shown FIRST in the extensions loaded section

Thank you so much for this... After spending an unfortunate amount of time attempting to TSHOOT this ridiculous issue, I came across your post/solution.

After a simple OS upgrade to Monterey, Apple support and your company's tech support recommends purchasing new cables to solve the issue?! When the issue didn't occur whatsoever on BigSur? That's completely senseless.

What's interesting is that I'm not using my internal panel in my setup, but setting the internal panel to 50 Hertz resolved the issue!

If this helps anyone, I'm currently using 3 external monitors with my laptop closed. The 3 external monitors are:

1. 1440p @ 60hz
2. 4k @ 60hz
3. 4k @ 60hz

Never had an issue till downgrading to Monterey.

Quick update on my dual monitor issue - I switched to 2 x USB digital AV multi port adapters. Both have HDMI connectors on them and this morning i connected my second monitor and VOLLA! I was JUMPing with JOY! Last night when i applied the updated to 12.1, my second screen did not work as i was using USB C to VGA. Anyways, i wanted to share my update in case it may help someone else's frustrations, like it was mine.

My monitor has a direct USB-C input, so it's just the USB-C to USB-C cable that LG supplied. Changing the DisplayPort settings to 1.2 just limits the bandwidth and refresh rate at certain resolutions, so it's probably that which fixed it. Similar to other people changing their refresh rates to under 60Hz.

I have to say it's not a perfect fix for me though, I've still had the odd crash/slow moment when changing between MacBook open and closed, as well as another crash when I unplugged an unused HDMI cable in the monitor. Apple definitely needs to provide a software fix asap.

I managed to get round this issue by doing the following:

• Setting the resolution to default for display
• Refresh to 50 Hertz

I have now not had a Kernel panic for 2 days, after continual crashes.

Consider downloading this little "discovery" utility, Etrecheck. It changes nothing. but it can produce an anonymized report that can be posted back on the forums.

Change its preferences to "allow full disk Access" before you say "GO".

Using EtreCheck to Troubleshoot Potential… - Apple Community

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I have a similar situation.

My Intel-Based MBP 16" 2019 has two SMK Link USB-C hubs https://www.smklink.com/products/usb-c-multi-port-hub, used to connect to 2 Samsung u32H85x 4K monitors via HDMI.

It worked great for a year through previous two OS releases, but is doing exactly what govindb describes, but only after initial unlock, then screen timeout due to idle timeout, and then resume.

I tracked it down to one specific monitor. Machine works great with internal screen, internal screen+monitor1 but dies whenever it is in internal screen+monitor1+monitor2 or internal screen+monitor2

I have done a thermal sensor reset and nvram reset and just did a full OS reinstall, the issue persists.

Those are the correct certified cables, and monoprice generally makes good stuff, but anything could fail.

You could swap just the computer ends and not have to re-pull. that would tell you if the issue followed cable+display.

Exactly what cables, adapters, and docks are you using to make the connection to each display. Please mention every device.

<< Yes, I disabled automatic graphic switching but it didn't help. >>

'automatic graphics switching' has NOTHING to do with this issue. Automatic graphic switching is not used when an external display is connected -- by Hardware design, ONLY the Discrete graphics processor is used when servicing external displays.

What I posted has to do with new Monterey feature: low-power/high-power mode.

I did that already, swapping out the cables between the docking stations, and then also swapping docking stations on the right-side ports.

Actually, I think I have to correct myself on this:

I tracked it down to one specific monitor. Machine works great with internal screen, internal screen+monitor1 but dies whenever it is in internal screen+monitor1+monitor2 or internal screen+monitor2

I am re-testing again and it seems like internal screen+monitor1 works and internal screen+monitor2 works, so only internal screen+monitor1+monitor2 does not (like the OP in this thread). The test cycle is 10 minutes long due to group policy mandated screen timeout...