External Displays Swapping - Arrangement Not Remembered!

[MrGunny94]

I WON! (paying)

Hello everybody and sorry for my english, I'll try to explain myself as clear as I can...
I've a Mac Studio and after few week of stress and trials seems that I finally found a solution for my configuration.
I use 4 displays: 1 Samsung 4kTV and 3 identical HP displays. Since last Saturday everything is working, displays now stays where I put them! How I made it? I spent some money on cables and I'm very disappointed in that, after buying a 3000euro computer!!!

At the beginning I bought 3 identical adapters from TB3 to HDMI:

uni Adattatore da USB Tipo C/Thunderbolt 3 a HDMI 4K (Luce LED, Alluminio, Nylon), Compatibile con Mac Studio, MacBook Pro/Air, iPad Pro/Air 5, Galaxy, Surface, XPS ecc.

uni Adattatore da USB Tipo C/Thunderbolt 3 a HDMI 4K (Luce LED, Alluminio, Nylon), Compatibile con Mac Studio, MacBook Pro/Air, iPad Pro/Air 5, Galaxy, Surface, XPS ecc.

www.amazon.it

So all 4 displays were connected using HDMI cables.

Back then displays were swapping and a very expensive NVME hdd, connected via USB4, gave me a lot of pain.
In order to make the disk work I had to unplug one or two displays randomly before turning on the Mac, then I could plug them back in. Seemed to me that the Mac had issues managing all the 4 TB3 ports simultaneously, maybe something power related.
I ended connecting the TV and two displays via TB3 ports and the third display via the onboard HDMI of the Mac.
That because with this configuration the TV(always) and the HDMI connected display(9 times on 10) stayed in place.

Then a colleague of mine bought the same identical machine and uses it with 3 different display models having no problem at all. So I went to his studio to test my disk on his machine bringing with me a fourth display and my adapters to replicate my setup and test the disk. I tried different configurations mixing his cables and my adapters and the outcome was that with two of his cables and one of my adapters the disk worked perfectly and the 4 different displays stayed always correctly placed.

His cables were TB3 ho HDMI, bought at the R-store so Apple certified.

Cygnett CY3305HDMIC cavo e adattatore video 1,8 m USB tipo-C HDMI Nero

Cygnett CY3305HDMIC cavo e adattatore video 1,8 m USB tipo-C HDMI Nero

www.amazon.it

So I decided to solve at least the disk issue and I bought two of this cables.
Thinking about the fact that the TV and the HDMI connected display were working finely and just the other two HP were still swapping become clear to me that I had to find a way to force the Mac to distinguish between the three identical displays.
Initially I thought about buying a powered TB3 Dock but the prices started from 300 euros so I refuse to spend all that money to solve a stupid Apple problem.
Then I realised that my displays have HDMI as well as DisplayPort connections.

I immediately bought a DP cable:

CABLEDECONN Cavo da USB C a DisplayPort 1.4 8K con USB-C PD Convertitore da 8K@60Hz 4K@144Hz Convertitore da Thunderbolt 3 a DisplayPort Compatibile con il Nuovo Mac Book Pro 2019 2020 2M

CABLEDECONN Cavo da USB C a DisplayPort 1.4 8K con USB-C PD Convertitore da 8K@60Hz 4K@144Hz Convertitore da Thunderbolt 3 a DisplayPort Compatibile con il Nuovo Mac Book Pro 2019 2020 2M

www.amazon.it

This cable need to be powered, so I had to but a USB-C power cable too.

Guys that worked!!

In the end my connection are:
TV via TB3 to HDMI cable
1st HP via TB3 to HDMI cable
2nd HP via TB3 to DP cable
3rd HP via onboard HDMI with a simple HDMI cable.

Everything works perfectly, now the machine can distinguish between the identical displays!!

The solution is, if you can, to use different type of connection for every identical display.
Hope to be helpful for someone at least.
Good luck!

Well this is one way to fix it, I'll give it a go.

 

[skivvie]

Another one here. MBP M1 16", clamshell with Studio display in middle of two hacked iMac 5Ks. Side monitors swap randomly. Gonna swap one to use Thunderbolt 4/USBC port instead of Display Port... I'm sure that will work, but ridiculous that we have to do so. Following, thanks for all the reports!

 

[skivvie]

Actually, yes that seems to have fixed it. I connected one of the boards (I'm using these: https://www.aliexpress.com/item/3256802548599862.html) with Displayport port and the other with the Type C Port, and it now gets the monitors straight. It screwed it up after the first plug in but now they seem to be sticking....

EDIT: Nope. Works MOST of the time, but today it swapped again. UGH.

 

[Rafterman]

I have seen the same issue occasionally, and I have a much simpler setup. A 16" MacBook Pro M1, going to an OWC Thunderbolt 4 dock, going to a Samsung 34" Thunderbolt 3 monitor. The MacBook is open, as the second monitor, the Samsung being primary.

While the monitors left/right position always stays put, the primary display switches to the MacBook for time to time (and the Samsung resolution, scaled to make things larger, switches back to default.)

So, I have seen a lot of people with more than one external monitor, clamshell, not clamshell, HDMI, DisplayPort, etc. And some people have "fixed" it with adapter or such. But I think it's just a software bug and isn't really fixable, maybe reduced at best with some of these random fixes people have been trying.

 

[devpatel87]

Unplug the dock and restart your machine to make it operational again.
Download fixing script attached here.
Unpack the archive, so that you have ResetDisplayPrefs.command in your Downloads folder.
Run Terminal and execute these commands to run the script:
cd ~/Downloads
chmod +x ResetDisplayPrefs.command
sudo ./ResetDisplayPrefs.command
The script has to be run with administrator privileges, this is required to forcefully delete defective system settings. Type in your password and press enter.
The script will display list of display-related settings files that will be deleted and will ask for confirmation before proceeding.
After confirmation the script will delete those files, forcing MacOS to recreate them from scratch.
After the script finishes it will ask you to reboot your machine. You can plug in your dock after reboot and the issue should be resolved.

 

[bbabaa]

I have never had this happen before until now. I went from an iMac with two thunderbolt LG 4K displays to a new Mac Studio and adding an LG 5K display along with the two LG 4Ks. This is when I noticed that when the system awakened from sleep my login prompt was no longer on the center display so after logging in I had to rearrange the displays. After this happened a few times, I sought an answer and found this thread.

That being said, since my displays are thunderbolt and not HDMI I needed another solution. And found these:

1. When I set my Studio to never sleep, and for several weeks, the screens were never rearranged.
2. But since I wanted to allow the system to sleep, I reset the Energy Saver to its default settings, and the rearranged display phenomenon is sometimes back. But now, I am noticing something new. If I awaken the Studio from sleep without using the touch ID sensor, I am presented with the login option. If the displays appear rearranged and the login prompt is relocated from the center display, rather than logging in, if I instead put the unit back to sleep by pressing escape, and then reawaken it a second or two later by pressing say the spacebar, my screens seem to return properly arranged on the second wake with the login prompt on the center screen. So now I can complete the login sequence via Touch ID or password. I think I can live with this as a suitable workaround as it requires only a few additional keystrokes and seconds.

Perhaps this will work for someone else?

 

[DJLC]

Since this thread is sort of still alive, I'll just say I've both experienced this and seem to have fixed it...

14" MBP / 10/16/16. Dual DIY 21.5" 4K iMac displays connected to an OWC TB3 dual DisplayPort adapter connected to an OWC TB4 dock.

When I first got both these displays going, I found it was swapping their positions every time it woke from sleep. I swapped the ports they were plugged into on my OWC adapter, and the behavior stopped. I won't be shocked if it reoccurs at some point, but it's been solid for a couple weeks now. FWIW, I seldom unplug my MacBook, and I half expect it might get confused again next time I take it somewhere.

I think the advice of "be sure to plug in your monitors from left to right" + thinking about the order in which macOS sees your various ports and adapters is somewhat helpful here.

Still, to be clear, I think there's some buggery here too that Apple needs to fix.

 

[LGSoftware]

I had the same problem and was able to resolve. In order to obtain the same position, your left monitor resolution needs to be set to "Default for Display" instead of being scaled. I suspect that upon returning from sleep the logic behind scaled resolution is simply placing the first monitor to awaken to the left position and the next monitor(s) to follow. I was seeing that my right monitor was coming awake before my left, therefore changing the position.

By making your left monitor resolution "Default", it will awaken more quickly from sleep than your right monitor (which I keep scaled). I've also been successful with both monitors being set to "Default".

 

[macsplusmacs]

I had the same problem and was able to resolve. In order to obtain the same position, your left monitor resolution needs to be set to "Default for Display" instead of being scaled. I suspect that upon returning from sleep the logic behind scaled resolution is simply placing the first monitor to awaken to the left position and the next monitor(s) to follow. I was seeing that my right monitor was coming awake before my left, therefore changing the position.

By making your left monitor resolution "Default", it will awaken more quickly from sleep than your right monitor (which I keep scaled). I've also been successful with both monitors being set to "Default".

What if on the left I have an LG 5K 27" turned vertical, which is still technically the default scale, and on the right I have another LG 5K 27" set to the default scale.

does orientation come into play here?

 

[LGSoftware]

What if on the left I have an LG 5K 27" turned vertical, which is still technically the default scale, and on the right I have another LG 5K 27" set to the default scale.

does orientation come into play here?

It's possible that being turned vertical causes a delay in awakening compared to your right monitor. Maybe your space allows you to try making your right monitor vertical instead of the left. I was desperate to try anything to resolve my issue. Just think in terms of what can you do to make your left monitor respond more quickly. Is the left monitor plugged in natively or does it use an external port?

 

[writerinserepeat]

Hey everyone. I just wanted to add another data point to this discussion.

Upgrade: Three identical 27" LG 5k displays with, of course, thunderbolt connections on my MBP M1 Max in clamshell.

Zero issues with monitors swapping locations or anything else for that matter, after daily reboots the past week.

Currently running MacOS 12.5, but was on 12.4 when I swapped out the BenQs I'd posted about previously for these great monitors.

Interesting that 3 thunderbolt-connected, identical monitors designed for Apple by LG have no issues.

Annoying of course, considering the aggravation I went through with my BenQs flip-flopping everywhere prior to the HDMI cable introduction resolving it (posted in prior messages), but still...interesting.

 

[macsplusmacs]

It's possible that being turned vertical causes a delay in awakening compared to your right monitor. Maybe your space allows you to try making your right monitor vertical instead of the left. I was desperate to try anything to resolve my issue. Just think in terms of what can you do to make your left monitor respond more quickly. Is the left monitor plugged in natively or does it use an external port?

I went down to a single LG 5K.

I had before the issue of this thread drove me bat crazy, this config:

Left -> Dell 4K (old model) vertical
Center -> LG 5K horizontal
Right -> Dell 4K (old model) horizontal

I just punted, I am hoping apple releases a new 6K or 7K display this fall, then I can start to think about just moving to one of these, possibly keeping the LG as well in vertical mode. undecided on that though.

 

[TBD072]

I had the same problem and was able to resolve. In order to obtain the same position, your left monitor resolution needs to be set to "Default for Display" instead of being scaled. I suspect that upon returning from sleep the logic behind scaled resolution is simply placing the first monitor to awaken to the left position and the next monitor(s) to follow. I was seeing that my right monitor was coming awake before my left, therefore changing the position.

By making your left monitor resolution "Default", it will awaken more quickly from sleep than your right monitor (which I keep scaled). I've also been successful with both monitors being set to "Default".

I've had both my identical monitors in 'default' resoultion and they keep swapping. Now trying 'default' on primary and scaled on secondary... fingers crossed!

 

[Cal2]

I was able to solve it by using two different brands of USBC to HDMI connectors. I have one from apple and another I purchased from Amazon compatible to M1 Macbook Pro). Hope this helps.

 

[LGSoftware]

I'm finding that if I have the supplied power adapter plugged in I am 100% less likely to have the monitors swap.

 

[ryanjfritter]

I WON! (paying)

Hello everybody and sorry for my english, I'll try to explain myself as clear as I can...
I've a Mac Studio and after few week of stress and trials seems that I finally found a solution for my configuration.
I use 4 displays: 1 Samsung 4kTV and 3 identical HP displays. Since last Saturday everything is working, displays now stays where I put them! How I made it? I spent some money on cables and I'm very disappointed in that, after buying a 3000euro computer!!!

At the beginning I bought 3 identical adapters from TB3 to HDMI:

uni Adattatore da USB Tipo C/Thunderbolt 3 a HDMI 4K (Luce LED, Alluminio, Nylon), Compatibile con Mac Studio, MacBook Pro/Air, iPad Pro/Air 5, Galaxy, Surface, XPS ecc.

uni Adattatore da USB Tipo C/Thunderbolt 3 a HDMI 4K (Luce LED, Alluminio, Nylon), Compatibile con Mac Studio, MacBook Pro/Air, iPad Pro/Air 5, Galaxy, Surface, XPS ecc.

www.amazon.it

So all 4 displays were connected using HDMI cables.

Back then displays were swapping and a very expensive NVME hdd, connected via USB4, gave me a lot of pain.
In order to make the disk work I had to unplug one or two displays randomly before turning on the Mac, then I could plug them back in. Seemed to me that the Mac had issues managing all the 4 TB3 ports simultaneously, maybe something power related.
I ended connecting the TV and two displays via TB3 ports and the third display via the onboard HDMI of the Mac.
That because with this configuration the TV(always) and the HDMI connected display(9 times on 10) stayed in place.

Then a colleague of mine bought the same identical machine and uses it with 3 different display models having no problem at all. So I went to his studio to test my disk on his machine bringing with me a fourth display and my adapters to replicate my setup and test the disk. I tried different configurations mixing his cables and my adapters and the outcome was that with two of his cables and one of my adapters the disk worked perfectly and the 4 different displays stayed always correctly placed.

His cables were TB3 ho HDMI, bought at the R-store so Apple certified.

Cygnett CY3305HDMIC cavo e adattatore video 1,8 m USB tipo-C HDMI Nero

Cygnett CY3305HDMIC cavo e adattatore video 1,8 m USB tipo-C HDMI Nero

www.amazon.it

So I decided to solve at least the disk issue and I bought two of this cables.
Thinking about the fact that the TV and the HDMI connected display were working finely and just the other two HP were still swapping become clear to me that I had to find a way to force the Mac to distinguish between the three identical displays.
Initially I thought about buying a powered TB3 Dock but the prices started from 300 euros so I refuse to spend all that money to solve a stupid Apple problem.
Then I realised that my displays have HDMI as well as DisplayPort connections.

I immediately bought a DP cable:

CABLEDECONN Cavo da USB C a DisplayPort 1.4 8K con USB-C PD Convertitore da 8K@60Hz 4K@144Hz Convertitore da Thunderbolt 3 a DisplayPort Compatibile con il Nuovo Mac Book Pro 2019 2020 2M

CABLEDECONN Cavo da USB C a DisplayPort 1.4 8K con USB-C PD Convertitore da 8K@60Hz 4K@144Hz Convertitore da Thunderbolt 3 a DisplayPort Compatibile con il Nuovo Mac Book Pro 2019 2020 2M

www.amazon.it

This cable need to be powered, so I had to but a USB-C power cable too.

Guys that worked!!

In the end my connection are:
TV via TB3 to HDMI cable
1st HP via TB3 to HDMI cable
2nd HP via TB3 to DP cable
3rd HP via onboard HDMI with a simple HDMI cable.

Everything works perfectly, now the machine can distinguish between the identical displays!!

The solution is, if you can, to use different type of connection for every identical display.
Hope to be helpful for someone at least.
Good luck!

SOLVED!!!! THANK YOU DARIO

This has been frustrating me for the longest time!

I have my 14" MBP hooked up to two identical Samsung monitors, and everytime I let my MBP fall asleep and rewake it, the 2 external displays were completely swapped - orientation, windows, etc, as if I physically moved my monitors and swpped their positions.

Both monitors were previously hooked up via HDMI cables. I simply swapped out one of the HDMIs with a DisplayPort cable, and voila! problem solved! I called Apple Support to inform them of this solution, and while it's not a system level solution, it worked for me!

Thanks again to Dario.

 

[BabblingBafoon]

I had this issue for years. Bought Stay, and not since. Worth a shot, believe they have a free trial.

@Lobwedgephil - are you saying you bought this app through the Mac App Store and have never had the problem since? And, if so, is that *still* the case all these months later? If so, to me it's worth $15!!!

‎Stay

‎If you’re fastidious about keeping your windows tidy, Stay is for you. Stay ensures that your windows are always where you want them to be, even as you connect and disconnect displays. Move your windows to where you want them, then have Stay store them. Once stored, windows can be returned to...

apps.apple.com

 

[BabblingBafoon]

You can see that the EDID of BOTH monitors is being read as the same Serial Number even though they are different monitors and really have different serial numbers.

BenQ SW270C_1.txt
Descriptor #1 - Serial number:
ETL6M00349SL0

BenQ SW270C_2.txt
Descriptor #1 - Serial number:
ETL6M00349SL0

That is what I have seen before when the problem occurs with otherwise identical monitors. This bug is apparently the reason that the Mac OS can not distinguish between the unique monitors when assigning them to locations and so they come up randomly assigned.

If your monitors had both a DVI and an HDMI input you could solve the problem by connecting one monitor with DVI and the other with HDMI, in which case the DVI EDID will have a different size than the HDMI EDID and the bug will definitely not come into play. But I don't think connecting one monitor with its HDMI input and the other with its DisplayPort or USB-C input will get around the bug and fix the problem. However you should try it if you have the correct cables, since it's a free try.

I've discussed the problem with Apple recently (the problem is not new, I originally had it in my 2010 Mac Pro and it has now reappeared), and it's inexplicable they haven't fixed it. I have no idea if or when they will fix it.

I don't believe over-riding the EDID in the Mac will be effective (because it probably can't keep straight which monitor is being over-ridden) but I haven't tried it. I don't know if that can still be done with the M1 chips (could be with Intel Macs), but if it can I'd try it since it would be free.

What should work would be an EDID emulator that sits between the Mac and the monitor (but I haven't needed to try that approach). You could try one of the cheap ones that could be returned with sufficient fixed features for your application (resolutions, HDCP support, etc), or a more expensive model that allowed you to copy the EDID from different monitor, or program custom changes (changes insignificant to your own usage).

Here's an example EDID emulator (I haven't tried one):

gofanco Prophecy 4K EDID Tester – 17 EDID Modes, Programmable EDID Copier & Manager, Amplifies & Equalizes Signal (4K @60Hz 4;4;4, HDR, HDMI 2.0a, HDCP 2.2, 18Gbps, CEC Pass-Through), TAA Compliant

www.amazon.com

Sorry, that's all I got.

I am betting what @PianoPro notates is a key issue. I have two of the same monitors plugged into a Plugable dock and both show the same EDID. I tried switching one from HDMI to DP in the dock (it has both HDMI and DP for each of the two monitor outputs) and the EDID stays the same. I just ordered a USB-C to DP adapter that should get to me tomorrow morning and will see if it shows a different EDID.

However, there may also be something to what @LGSoftware says around the left-most monitor coming up first being important for the swapping. My left monitor is set to 90º Portrait, so that likely makes it take longer to come up and therefore gets seen as the second monitor. So, when mine happens, like others using a portrait monitor, it also swaps orientation... making fixing it more difficult to navigate.

I will try to remember to post back if the DP adapter, which I will plug directly into the MBP instead of the dock, fixes the issue.

 

[BabblingBafoon]

Well, the USB-C to DP adapter didn't solve the problem for me. That being, one of my monitors plugged into my Plugable TB3 dock via HDMI and the second one (the left most monitor) plugged into the USB-C to DP plugged directly into the MBP via a different TB port than the dock. Sleep/wake... swapped. 😑

I could try what @LGSoftware mentioned around repositioning monitors, but I think that would require changing where my dual-VESA arm mount is on my desk, which would also require drilling a new large hole in my Walnut desk... not really interested in that. <sigh>

Other possible fix, get a different second monitor. Since my left monitor is portrait mode (90º), I'm less worried that they match.

Editing/updating to add:
I have my MBP set to "prevent from going to sleep" and I turned off the schedule to have it sleep overnight. For me, it was only swapping displays on reboot or waking from truly sleeping (not just the displays sleeping). So, while I'll still have to deal with it on reboots, it should minimize how impactful it is. I may also shorten how long before the displays turn off and use the "Amphetamine" app during the day to keep them active if I'm reading something without interacting.

Finally, my specific monitors are likely an even worse situation that others. SwitchResX showed that they both are literally identical with no unique identifier at ALL! to where I could only make certain changes to the first of them in SwitchResX, and changing the name of one in there changed the name to both. 🙄 I think this also explains why using a different adapter/port made no difference.

 

[andyrharvey]

Well, the USB-C to DP adapter didn't solve the problem for me. That being, one of my monitors plugged into my Plugable TB3 dock via HDMI and the second one (the left most monitor) plugged into the USB-C to DP plugged directly into the MBP via a different TB port than the dock. Sleep/wake... swapped. 😑

I could try what @LGSoftware mentioned around repositioning monitors, but I think that would require changing where my dual-VESA arm mount is on my desk, which would also require drilling a new large hole in my Walnut desk... not really interested in that. <sigh>

Other possible fix, get a different second monitor. Since my left monitor is portrait mode (90º), I'm less worried that they match.

Editing/updating to add:
I have my MBP set to "prevent from going to sleep" and I turned off the schedule to have it sleep overnight. For me, it was only swapping displays on reboot or waking from truly sleeping (not just the displays sleeping). So, while I'll still have to deal with it on reboots, it should minimize how impactful it is. I may also shorten how long before the displays turn off and use the "Amphetamine" app during the day to keep them active if I'm reading something without interacting.

Finally, my specific monitors are likely an even worse situation that others. SwitchResX showed that they both are literally identical with no unique identifier at ALL! to where I could only make certain changes to the first of them in SwitchResX, and changing the name of one in there changed the name to both. 🙄 I think this also explains why using a different adapter/port made no difference

 

[Tracyf]

I am running 14" MBP with two external displays and the monitors will not keep their position to the left/right every time I wake from sleep or plug back in. The monitors are arranged above my MacBook Pro (see below), with the monitor on the left connected via a USB-C dock and hte monitor on the right via HDMI.

View attachment 1881849

After waking the computer, the monitor on my left will be on the right and vice versa so I have to go into the display settings and drag-and-drop them back into place.

The only thing I can think of is that each monitor is the same brand/model and perhaps that is causing an issue. I'm not sure if this is an OS Monterey or hardware issue. I've tried ensuring I plug-in the computer in the same order or make different monitors (including the MBP display) as the 'primary' monitor, but nothing seems to work. I have not tested using a different USB C dock solution or ocnnected directly to the left monitor via a USB-C-to-HDMI adapter in case the dock is causing the issue, but that doesn't really make sense to me.

Is there a way to perhaps adjust the names or behavior of the displays to trick the OS into remembering one should always be on the left?

View attachment 1881850
My exteneral displays - same model.

I appreciate any insight or help!

This is happening to me every day. Two external monitors of same type (HP), plugged into docking station. If

I am running 14" MBP with two external displays and the monitors will not keep their position to the left/right every time I wake from sleep or plug back in. The monitors are arranged above my MacBook Pro (see below), with the monitor on the left connected via a USB-C dock and hte monitor on the right via HDMI.

View attachment 1881849

After waking the computer, the monitor on my left will be on the right and vice versa so I have to go into the display settings and drag-and-drop them back into place.

The only thing I can think of is that each monitor is the same brand/model and perhaps that is causing an issue. I'm not sure if this is an OS Monterey or hardware issue. I've tried ensuring I plug-in the computer in the same order or make different monitors (including the MBP display) as the 'primary' monitor, but nothing seems to work. I have not tested using a different USB C dock solution or ocnnected directly to the left monitor via a USB-C-to-HDMI adapter in case the dock is causing the issue, but that doesn't really make sense to me.

Is there a way to perhaps adjust the names or behavior of the displays to trick the OS into remembering one should always be on the left?

View attachment 1881850
My exteneral displays - same model.

I appreciate any insight or help!

Same! I have two external monitors of same model, plugged into docking station. Whenever I power off and power machine back on, it reverses the position of the monitors. I find that if i move the power cord back and forth between the two positions on the laptop, it eventually sets the monitors to the right position without me having to go into the settings. Super annoying though.

 

[andyrharvey]

I had this problem on a 2019 Macbook Pro and it remained, unchanged when I upgraded to a Macbook Pro 2022 - both using identical twin monitors. In both MBPros there is no problem when used on another setup of two dissimilar external monitors.

I seem to have solved this problem for me - I have now had no random swapping of monitors during the last 20 or so wakes from sleep. I think the problem may have been associated with both monitors having the same (default) name - with (1) and (2) appended. I did this sequence:

1) I unplugged the right monitor and used switch SwitchResx to change the name of the left monitor to "Left"
2) I unplugged the left monitor, replugged the right monitor and changed its name to "Right"
3) I replugged the right monitor
The two monitors now have different names and everything works fine - the different names could be confirmed by eg looking at Display Preferences or "About this Mac"

Strangely, after about 10 mins the name of the Left Monitor changed to "Right" so both monitors now have the same name. I've repeated this process with the same outcome - but nevertheless it has solved the problem. This is what it looks like now:

 

[Williamsr81]

So I don't know if this is going to help or not, but I was able to identify a short path to "fix" this.

I installed homebrew and then installed the DisplayPlacer utility using Terminal.

Homebrew: /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

DisplayPlacer: brew tap jakehilborn/jakehilborn && brew install displayplacer

Once DisplayPlacer is installed arrange your monitors how you want them open Terminal and run the command: displayplacer list

This will give you an output that looks like this.

"id:37D8832A-2D66-02CA-B9F7-8F30A301B230 res:1728x1117 hz:120 color_depth:8 scalingn origin0,0) degree:0" "id:8EDCC4C2-9BB1-461F-B96F-EC0BE9D304BA res:1920x1080 hz:75 color_depth:8 scalingff origin1728,0) degree:0" "idAF6A076-DBDC-4A36-8F82-471F341127F8 res:1920x1080 hz:75 color_depth:8 scalingff origin3648,0) degree:0"

In Automator write a shell script workflow using this output.

Mine looks like this:

/opt/homebrew/bin/displayplacer "id:37D8832A-2D66-02CA-B9F7-8F30A301B230 res:1728x1117 hz:120 color_depth:8 scalingn origin0,0) degree:0" "id:8EDCC4C2-9BB1-461F-B96F-EC0BE9D304BA res:1920x1080 hz:75 color_depth:8 scalingff origin1728,0) degree:0" "idAF6A076-DBDC-4A36-8F82-471F341127F8 res:1920x1080 hz:75 color_depth:8 scalingff origin3648,0) degree:0"

I found this part "/opt/homebrew/bin/displayplacer" by running in Terminal: which displayplacer

Once saved you can open the workflow with Shortcuts. This creates a shortcut program that can be pinned to the menu bar for easy access.

When the monitors rearrange themselves, run the shortcut and it should at least alleviate some of the basic frustration.

Please ignore the emojis.

 

[macsplusmacs]

what does this do casket?

jakehilborn/jakehilborn

?

 

[DJLC]

So I don't know if this is going to help or not

I'm not sure either, but I'm sure gonna give it a shot!

FWIW, I thought I had this fixed. But no. Not really. It just happens less frequently. My current "fix" is to turn off my displays + turn them back on from left to right. That works every time. But it's annoying and involves physical effort; a shortcut would be real nice until Apple fixes it... 😜