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Library module Using 2 external displays with my macbook pro...

Morris Taub

Premium Classic Member
May 17, 2016
Lightroom Experience
Lightroom Version
Lightroom Version Number
Operating System
  1. macOS 14 Sonoma
but display 2 won't stay on if i use the graphic processor so I leave it off...

it isn't the end of the world...the computer/lightroom/photoshop is damn fast even with it off...

and when i click it on I just have to go and click on [2] to get my second monitor to show me an image on the second monitor...

I've switched around cables, trying display port to displayport for monitor 2 and usb c to displayport...it doesn't help...

I wonder if it is because my monitors are old...both NEC, monitor 1 is a 2690wuxi 25" attached hdmi to dvi-i and monitor 2 is a PA271Q displayport (off my caldigit ts4) to the monitor. I tried monitor 2 with a usb c cable to displayport, direct to computer usb c and also via the TS4 and the issue isn't resolved.

Ok. That's all I got. I tried search here and on the adobe community and nothing is exactly like what i'm experiencing so I thought I'd ask here and see if someone has something similar going on.

Including system info below. Not sure it helps, but what do I know.


Lightroom Classic version: 13.4 [ 202406181129-60d181b7 ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 14
Version: 14.4.1 [23E224]
Application architecture: arm64
Logical processor count: 14
Processor speed: NA
SqLite Version: 3.36.0
Power Source: Plugged In, 80%
Built-in memory: 36,864.0 MB
Dedicated GPU memory used by Lightroom: 939.3MB / 27,648.0MB (3%)
Real memory available to Lightroom: 36,864.0 MB
Real memory used by Lightroom: 9,459.3 MB (25.6%)
Virtual memory used by Lightroom: 421,800.7 MB
Memory cache size: 2,683.2MB
Internal Camera Raw version: 16.4 [ 1897 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2
Camera Raw virtual memory: 1002MB / 18431MB (5%)
Camera Raw real memory: 1082MB / 36864MB (2%)

Preview1- RAM:22.0MB, VRAM:0.0MB, DSCF6120.RAF
Preview2- RAM:22.0MB, VRAM:0.0MB, DSCF6121.JPG
Final3- RAM:189.0MB, VRAM:0.0MB, DSCF6119.JPG
Final4- RAM:189.0MB, VRAM:0.0MB, DSCF6120.JPG
Preview5- RAM:22.0MB, VRAM:0.0MB, DSCF6117.JPG
Preview6- RAM:22.0MB, VRAM:0.0MB, DSCF6117.RAF
Preview7- RAM:22.0MB, VRAM:0.0MB, DSCF6118.RAF
Preview8- RAM:22.0MB, VRAM:0.0MB, DSCF6121.RAF
Preview9- RAM:22.0MB, VRAM:0.0MB, DSCF6122.JPG
Final10- RAM:189.0MB, VRAM:0.0MB, DSCF6119.RAF
Preview11- RAM:22.0MB, VRAM:0.0MB, DSCF6118.JPG
NT- RAM:743.0MB, VRAM:0.0MB, Combined:743.0MB

m:2,683.2MB, n:1,776.7MB

U-main: 135.0MB

Standard Preview Size: 2880 pixels
Displays: 1) 3024x1964, 2) 1920x1200, 3) 2560x1440

Graphics Processor Info:
Metal: Apple M3 Max
Init State: GPU for Export supported by default
User Preference: Off

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Volumes/Lr.cat.2019.previews/morristaub.2009-2-2/morristaubphotography-2-v13-3.lrcat
Settings Folder: /Users/morristaub/Library/Application Support/Adobe/Lightroom

Installed Plugins:
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) DxO PhotoLab 7
4) DxO PhotoLab 7 Importer
5) Flickr
6) Nik 6 HDR Efex
7) Nikon Tether Plugin

Config.lua flags:
I wonder if it is because my monitors are old...both NEC, monitor 1 is a 2690wuxi 25" attached hdmi to dvi-i and monitor 2 is a PA271Q displayport (off my caldigit ts4) to the monitor. I tried monitor 2 with a usb c cable to displayport, direct to computer usb c and also via the TS4 and the issue isn't resolved.

I don’t have a good answer, just contributing that I don’t think it’s the age of the displays.

My M1 Pro MacBook Pro on macOS 14.5 is running two displays through an OWC Thunderbolt dock, and it is stable.
One display is from 2015 (NEC PA272), and the other display is from 2007 and running through a DVI adapter.
On this configuration I use Lightroom Classic with the Secondary Display on my other display practically all the time.

On my Mac the main cause of seeing a display go black is if I attach a third display, because an M1 Pro supports only two external displays. But your M3 Max doesn’t have that limitation, so even if you are connecting a third display it shouldn’t cause another display to go black.

Another cause can be when I’m running the BetterDisplay app and click an advanced setting that these old displays don’t like. I only mention that in case you’ve installed any power-user display software; if so, try updating or disabling it and see if it improves.
I use an M1 Max MBP 16” and also two (4K) monitors. No issues whatsoever. It could indeed be a non-standard resolution setting. I use SwitchRes X and it has a wealth of settings, but not every one may be good for a particular monitor.
I'm guessing it's either the dock or resolution as noted earlier.

I've also recently upgraded to a MacBook Pro M3 Max (Sonoma 14.5) and it works really well with 2 monitors. I'm using an old Plugable Thunderbolt 3 dock with two older Philips 24" monitors. One monitor plugs into the HDMI port on the dock and the other is via DisplayPort. I would have preferred them both use the same interface but the dock only has one of each and I didn't want to use an adapter unless I have to. I haven't had any problems with it. Only two slightly weird things are the monitor with DisplayPort goes in and out of sleep often when the laptop is sleeping. It doesn't affect anything other than the monitor displays a message saying it is going back to sleep. When awake it is 100% stable. The only other thing is Lightroom Classic opens randomly on one monitor or another and I have to drag it across to where I want it. Sometimes it remembers across restarts and other times it doesn't.
I think the latter may have something to do with Apple’s “Spaces”. I don’t use Spaces and so I have only one monitor with the menu bar. The other monitors do not have a menu bar. Then I use Lightroom Classic with the main window in ‘Full screen with menu bar’, so that means Lightroom Classic cannot place the main window on any other screen, even if it wanted to.
Thanks Johan for the suggestion. I do use Spaces so maybe that's the source of the issue. I like them because I often have multiple things going at once and switch back and forth. But I'll switch Spaces off and give your suggestion a try even if just as a test