macOS stutters every 2 seconds when an external monitor is plugged in

[DiPech]

I’ve bought a new Macbook Pro 16”. There is stuttering right after I have my external monitor plugged in. Stuttering is observed on both displays (on the internal Retina and the external LG display) while having connected the external LG display. Stuttering stops immediately right after ejecting the LG display.

There are two videos I’ve recorded to show this problem (3 lags during two 6-seconds videos):

Stuttering when moving a window:

Stuttering when selecting a text:

My specs:
Notebook: Macbook Pro 16” 2019, 8-Core Intel Core i9, 16 GB RAM, 1TB SSD, Intel UHD Graphics 630, AMD Radeon Pro 5500M (4GB).
External Monitor: LG 29UM69G 29”.
OS Version: Catalina, 10.15.5 (19F101).
Periphery: Magic Keyboard 2, Magic Mouse 2, USB 2.0 no-name Mouse, original Apple USB-C to USB-C 0.8M cable (Apple Thunderbolt 3), HDMI to HDMI cable through original 3-in-1 adapter USB-C to [ USB-C, HDMI, USB 2.0 ].

What doesn’t help at all:

• Installing the last update.
• Connecting through USB-C-to-USB-C Thunderbolt 3 cable (instead of HDMI-to-HDMI plus HDMI-to-USB-C connector) – I’ve bought it just for solving this issue.
• Resetting SMC and NVRAM.
• Using another (new) user.
• Closing the lid and working only with the external display.
• Having both displays working but showing separate desktops.
• Having both displays working with turned on displays mirroring.
• Setting custom scaling (also tried choosing custom scaling by pressing Option key).
• Using the built-in trackpad.
• Turning off Bluetooth.
• Using no-name USB2.0 wired mouse.
• Removing mouse and trackpad plists from Libraries/Preferences folder.
• The Diagnostic Tool (by pressing D) shows “No Issues Found”.
• The Disk Utility Tool (by pressing Cmd + R) shows “No Issues Found”.

What helps (but these are not solutions):

• Eject external display.
• Using Bootcamp (this problem is not observed there at all).
• Booting in Safe Mode (by pressing Shift after starting a computer).
• Using my previous MacBook Pro 2015 15” (which also works under the last Catalina version) with the LG display.

Please, don’t offer these possible solutions, they aren’t acceptable for me:

• Return the MacBook to the store.
• Reinstall macOS from scratch.

P.S. AppleCare support doesn’t help me

Please, can anybody help with it?

 

[jmsmuy]

I had that issue (you posted in the thread i had created), my "solution" to this day is that the issue resolves itself a little while after plugging the monitor in, i can't pinpoint what the issue is, but since it goes away a bit after i start using the mac i stopped being bugged by it.

 

[DiPech]

I had that issue (you posted in the thread i had created), my "solution" to this day is that the issue resolves itself a little while after plugging the monitor in, i can't pinpoint what the issue is, but since it goes away a bit after i start using the mac i stopped being bugged by it.

Yes, I saw your message about it. But for me, it doesn't work. I've been experimenting with it for two weeks without any progression
So, I'm still searching for some solution or workaround.

 

[Hiredgoon6]

Check out the other 16" stuttering threads. I have this issue on 10.15.5 and forcing discrete graphics to run is the only fix known.

 

[DiPech]

Check out the other 16" stuttering threads. I have this issue on 10.15.5 and forcing discrete graphics to run is the only fix known.

Hi, Hiredgoon6! Unfortunately, it doesn't work for me. I've tried it by disabling "Automatic Graphics Switching" and forcing using the discrete card with gfxCardStatus.

Could you describe what did you additionally do to solve this problem?

 

[s66]

Not sure how easy these T2 macs can still boot from external media: but try installing a perfect clean copy of macOS without any changes , tweaks, or 3rd party software on an external disk.
If your problem is gone: you now know it's something on the software side - which given the lack of many hunderds of others complaining is something I 'd venture as the cause.You can then try to add software and settings you want to that 2nd copy of macOS one by one till it reappears: you'll have found the culprit.

 

[DiPech]

try installing a perfect clean copy of macOS without any changes , tweaks, or 3rd party software on an external disk.

Hi, s66! Thanks for the answer! I'll research how to do it.

 

[Taz Mangus]

Hi, s66! Thanks for the answer! I'll research how to do it.

You could create a new APFS partition on your internal drive and clean install Catalina to that. Might be able to avoid having to disable SIP as you won’t be booting from an external drive.

 

[AAPLGeek]

Trying using native retina res instead of custom scaling

 

[MacGizmo]

If you booted into Safe Mode and had no issues, then the problem is a piece of software you have installed that is NOT part of the base macOS. Do you have Logitech mouse/keyboards? If so, you have .kxt files known to be problematic. If there are any non-Apple icons in the menubar, delete the apps or prevent them from launching at startup. Running via 3rd party VPN app? Stop using it.

The problem is clearly software conflict, as evidenced by you having no issues with Bootcamp or Safe Mode startup.

No need to start up from external drives, or reinstall the macOS. But you may have to delete a bunch of your apps to nail down the culprit. And by "delete the apps," I mean thoroughly—not just the app in the Applications folder, but all signs of it from all three Library folders (preferences, application support, startup daemons, startup items, components, containers, etc.)

 

[Taz Mangus]

If you booted into Safe Mode and had no issues, then the problem is a piece of software you have installed that is NOT part of the base macOS. Do you have Logitech mouse/keyboards? If so, you have .kxt files known to be problematic. If there are any non-Apple icons in the menubar, delete the apps or prevent them from launching at startup. Running via 3rd party VPN app? Stop using it.

The problem is clearly software conflict, as evidenced by you having no issues with Bootcamp or Safe Mode startup.

No need to start up from external drives, or reinstall the macOS. But you may have to delete a bunch of your apps to nail down the culprit. And by "delete the apps," I mean thoroughly—not just the app in the Applications folder, but all signs of it from all three Library folders (preferences, application support, startup daemons, startup items, components, containers, etc.)

Booting into Safe Mode does not necessarily mean that a user installed third party software is causing an issue. As I recently have come to understand, in Safe Mode there a quite a few Apple kernel extensions that are not loaded: https://eclecticlight.co/2019/11/08/safe-booting-in-catalina-has-changed/.

 

[Taz Mangus]

My suggestions are to try:

• Boot into Recovery Mode, download and install the 10.15.5 full installer and install it in Recovery Mode. This is different then just applying the last update. The full installer will refresh all the OS system files.
• Do what I suggested in post #8, create a new partition on your internal drive and clean install Catalina to the new partition. Boot to the new partition, don't install anything and try and see if the stuttering happens. If it does then you know it is probably a OS issue. If it does not happen than you know it maybe something you have installed. Either way, boot back to your normal partition and remove the new partition.

How to reinstall macOS - Apple Support

You can use macOS Recovery, your computer's built-in recovery system, to reinstall the Mac operating system. Reinstalling macOS doesn't remove your personal data.

support.apple.com

 

[DiPech]

But you may have to delete a bunch of your apps to nail down the culprit. And by "delete the apps," I mean thoroughly—not just the app in the Applications folder, but all signs of it from all three Library folders (preferences, application support, startup daemons, startup items, components, containers, etc.)

Boot into Recovery Mode, download and install the 10.15.5 full installer and install it in Recovery Mode. This is different then just applying the last update. The full installer will refresh all the OS system files.

Do what I suggested in post #8, create a new partition on your internal drive and clean install Catalina to the new partition. Boot to the new partition, don't install anything and try and see if the stuttering happens. If it does then you know it is probably a OS issue. If it does not happen than you know it maybe something you have installed. Either way, boot back to your normal partition and remove the new partition.

Thanks for the advice! Unfortunately, I won't have enough time for that this week. I'll try it a little bit later.

 

[gmh]

For what it's worth a full reinstall of macOS via Recovery Mode did not solve the problem for me. The stuttering was there from the moment the display reconnected during the installation process (one of the gray installation screens). I didn't install on a new partition though.

 

[DiPech]

I also did a completely fresh installation. The problem is still here...
Does it mean that the problem is a kind of software bug? Something is wrong with macOS Catalina 10.15.5, isn't it?

 

[JordanWander]

I have the same issue. completely new machine. No additional apps yet. Works fine in safe mode.Works fine when monitor isn’t plugged in. I also tried the 10.15.6 beta and the 10.16 beta. Both had the same exact behavior. My 15.4 inch mbp works fine with the same monitor. Massively frustrating.

 

[Taz Mangus]

I also did a completely fresh installation. The problem is still here...
Does it mean that the problem is a kind of software bug? Something is wrong with macOS Catalina 10.15.5, isn't it?

I have the same issue. completely new machine. No additional apps yet. Works fine in safe mode.Works fine when monitor isn’t plugged in. I also tried the 10.15.6 beta and the 10.16 beta. Both had the same exact behavior. My 15.4 inch mbp works fine with the same monitor. Massively frustrating.

My suggestion, at this point, would be to open a case with Apple Support.

 

[DiPech]

My suggestion, at this point, would be to open a case with Apple Support.

I've done it five times. I called them twice, and three times had a text chat with support. All their recommendations were like "fully reinstall macOS", "try with different monitor" or "bring your notebook to us".

Anyway, I've created a similar post in Apple Community. Could anybody who is facing the same problem leave a comment under it and mark the post with "I have this question too" button?
I guess they would notice the problem if many people showed an activity under the post...

https://discussions.apple.com/thread/251465302

 

[gmh]

I spent at least an hour on a chat with Apple support. We kept going in circles with he agent insisting it was a problem with the monitor and not the Macbook. Eventually it was escalated and the manager person wanted to have an "engineer" call me. The phone rang, I waited on hold, then the line went dead. And since it had been handed off the chat session had been closed. Really frustrating.

@DiPech I added a link to my Apple Discussions thread in yours.

 

[EdwXDD]

Whenever a non HDCP compliant monitor is plugged in, or there is any HDCP handshake issue, the below log will be shown continuously:
/System/Library/Extensions/AMDRadeonX6000Framebuffer.kext/Contents/MacOS/AMDRadeonX6000Framebuffer

19:53:46.916991+0800 kernel [3:0:0] [HDCP:3] runEvent() !!! Action is stall currentTime: 162560171947197, nextTime: 162560371941098, crtc: 3!

And the cursor will be stalled for every 2~3 seconds.
If you are having the same problem, please help submitting the feedback to Apple via https://www.apple.com/feedback/macbookpro.html (or is there other better channel for this?)
Just hoping when there is more vote, it will be fixed finally in the future macOS update.

p.s. My workflow consists of non HDCP compliant monitors, and I don't play copy protection content. So yes sometimes replugging HDMI cables or replacing the a better HDMI cable can solve the HDCP handshake issue, but I don't think this lag should happen in the first place. It is not happening on the Mac Pro 2013 (D500 x2) or Mac Pro 2019 (Pro Vega II x 2).

 

[Hiredgoon6]

Can confirm that 10.15.6 did NOT fix after a few days of testing.

 

[sharpie88]

Do you by any chance have a Wacom tablet or similar device that is connected but not turned on? I had a similar issue that resolves when I either turn on the Wacom tablet or disconnect it when I'm not using it. If that doesn't solve your issue the issue is definitely with your monitor. The computer is having difficulty maintaining a solid connection. Could be a bad circuit in the monitor itself. Try connecting a different display and see if that solves the problem.

 

[maksimt]

Whenever a non HDCP compliant monitor is plugged in, or there is any HDCP handshake issue, the below log will be shown continuously:
/System/Library/Extensions/AMDRadeonX6000Framebuffer.kext/Contents/MacOS/AMDRadeonX6000Framebuffer

19:53:46.916991+0800 kernel [3:0:0] [HDCP:3] runEvent() !!! Action is stall currentTime: 162560171947197, nextTime: 162560371941098, crtc: 3!

And the cursor will be stalled for every 2~3 seconds.
If you are having the same problem, please help submitting the feedback to Apple via https://www.apple.com/feedback/macbookpro.html (or is there other better channel for this?)
Just hoping when there is more vote, it will be fixed finally in the future macOS update.

p.s. My workflow consists of non HDCP compliant monitors, and I don't play copy protection content. So yes sometimes replugging HDMI cables or replacing the a better HDMI cable can solve the HDCP handshake issue, but I don't think this lag should happen in the first place. It is not happening on the Mac Pro 2013 (D500 x2) or Mac Pro 2019 (Pro Vega II x 2).

Where are you seeing this console message? When I look in Console and search for ANY:HDCP I don't get any log messages.

I have the mouse stutter on my base 16" MBP on 10.15.6 when I plug in my QNIX 3216R 4k monitor via a DP->USB-C cable. I also have the same stutter connecting the monitor via a DP->USB-C hub. I don't have the stutter when connecting a Dell 38" ultrawide via the same DP->USB-C cable and a Dell 27" 1080p display via a USB-C->HDMI hub. I don't have the mouse stutter on the QNIX 3216R 4k monitor when using my 2017 13" MBP >_<.

 

[maksimt]

I got lucky... I managed to update the firmware on my monitor, and this fixes the cursor stuttering issue.

My monitor (the QNIX UHD3216R) had a relatively well known HDCP issue discovered by PS4 Pro Users. The manufacturer released a firmware update to fix HDCP support. After seeing posts that the cursor stutter occurs because of failed and retried HDCP syncs, I thought the two may be related.

I still think the macOS Radeon drivers shouldn't make monitors with broken HDCP implementations unusable. The same monitor didn't have any issues with my 2017 13" MBP.

 

[OlivierLarue]

Exactly same issue here.

External monitor : DELL U3415W (3440 x 1440 @ 60 Hertz)

Working perfectly with my Macbook Pro 13" 2015.

MacBook Pro (16-inch, 2019)
2.4 GHz 8-Core Intel Core i9
AMD Radeon Pro 5500M 8 GB

Plugged with the official USB-C to HDMI Apple adapter.

This is the 2nd MacBook Pro (16-inch, 2019) I'm testing on as I returned the 1st one thinking it was faulty...

I tried several resolutions settings, fresh/clean re-install... Nothing worked...