MacOS Monterey display resolution problem

I have found a temporary quick fix for a stretched out resolution after disconnecting an ultra-wide display:

Change the refresh rate to another refresh rate like 60hz, then switch it back to pro-motion.

As such, you don't have to restart your mac every time.

Details:

• 5120 x 1440 49'' Samsung DQHD Mini LED Gaming ultra-wide Monitor Odyssey Neo G9.
• 16" M1X Macbook Pro with macOS Monterey 12.3.1.

Update. I finally got it to work. I tried all the options that had been presented in here up to the point of this post and nothing worked. But... I decided to try to switch dongles and see if that worked. It did—so for others struggling, try a new connection port from your HDMI cable into your USB-C supported Macbook.

It seems odd, as the size of the elements on screen seems identical, it is like the display aspect ratio is wrong.

Which of the two displays is set as your "Main display"? The built-in or the Dell?

Are you using them mirrored or as extended desktop?

When you have to go to System Preferences->Displays, after disconnecting, and change the resolution, what is selected?

Wait.... I just went looking for the monitor, and it appears to one of those very wide displays (5120x1440, or something like that?)

That may be related.

What is the display resolution you are using on the external? If you are mirroring, are you "optimizing for external display" or for the built-in?

I would start by making sure that your internal is set as the main display, and that you are using as extended desktop, not mirroring - see below. If the problem persists, at the moment I don't know what else to try.

Are you mirroring the two displays?

Since the two have very different aspect ratios, something has got to give.

I suggest you use extended desktop in order to use each display at their best resolution.

Hi immortalkid,

I've been using an old program called Retina DisplayMenu (RDM) from 2012 to change the display resolution and refresh rates on both the Macbook and the external monitors. It's in perpetual beta, but I've been using it for almost ten years and it still seems to work fine on Monterey. It was distributed free without limitations and you can get it from here.

Looking for I also just found another similar free program at the App Store, but I haven't yet tested that, so can't say if it's any good.

That didn't work for me. MacOS kept switching back to display mirroring.

My gear is MBP 2017 13".

External (primary) monitor is a new LG 29NW600 which is a 29" ultra-wide.

Checking in System Information under USB and shows this as a "Billboard device" with a SN of 1234577890ABCEDF.

Was using the LG software for splitting screen into zones but it would periodically start the spinner and after a while screens would flip off and on, both on laptop screen and the display.

I normally work with laptop closed and just use the external.

As mentioned in other posts the resolution keeps getting set back to 1080p instead of its own native. Setting to scaled doesnt help.

Have now turn off the LG control software and installed BetterDummy https://github.com/waydabber/BetterDummy/tree/v1.0.13 which seems to have solved the issue - at least it has kept the settings after a reboot which is already way better than macOS most of the time!

Neat, just installed SwitchResX and I’m liking it a lot - problem solved 👍

xtngo39 wrote:

Hi all,

After unplugging the thunderbolt cable from my Dell U4919DW from my Macbook Air M1, the display resolution changes into some weird resolution that doesnt fit my macbook screen.... I have to go into display setting in the System Preference to change it back to make it usable. Can anyone tell me whats going on? Will this be fix in the next MacOS Monterey software up? Thanks

Toggle between mirrored and extended and compare your results

I use my mac with external displays and projectors every day, in class, at home or office.

Several different resolutions, sometimes using extended desktop, others mirroring.

I have never experienced what you describe. When disconnecting the external display, the internal has always returned to what it was before.

My first idea was to suggest resetting NVRAM. Now this apparently works differently in M1 macs (which I don't have yet).

Apparently one is supposed to shut down (not restart), wait some fifteen seconds then start again. Any difference?

I wanted to keep this thread going, as i have a similar issue with my new Macbook Pro (13-inch, M1, 2020). When starting the machine up plugged into external display, sometimes the macbook retina display is stretched, and the mouse cursor is missing. When I log into the user, everything on the retina display is stretched so much that the dock isn't reachable. I never had this issue on my 2017 MBP model using the same external monitor

My external display is a Samsung Odyssey 49" ultra wide monitor (C49HG9x). I must restart the computer without the external monitor connected and then connect the monitor after the OS fully loads and I log in. The resolution on the external monitor is always as expected, and this behavior only occurs on the built-in retina display.

I would like to share my experience as well. Unfortunately most of the troubleshooting in this thread did not help. I cannot get refresh rate to show up at all, even using the option key. I've messed with a lot of different settings and the only thing that works is to set it to a lower resolution.

My external monitor or the laptop is not correctly recognizing the right resolution. On the Macbook, in the display settings, it correctly notes that it should be set to 3440x1440 (and the external monitor settings repeat that, adding in @100 refresh). However, when I have it set to that, the Macbook says that it is instead being set to 4302x1440 (external monitor adds that it is @60 refresh).

For now, the only recourse I have, without any ability to get to the refresh rate settings, is to operate on a lower resolution of 2560x1080.

It is the same on my computer after update as well.

My research in internet showed, that happened literally to everyone.

I was really angry as I saw it and spent a lot of time to check what really happened and what. I thought, it could be firmware of monitor. But no, apple just cut amount of given resolutions. And any workaround (BetterDummy, SwitchResX) doesn't work for me. Very-very sad.

Suddenly, my monitor started working again and the 3440X1440 started showing in my system preferences. I tried all the apps and fixes mentioned above, none of them worked. But I updated my system from 12.1 to 12.2. In the first 24 hours nothing happened and I kept experimenting with custom resolutions on SwitchResX, which didn't work. Then suddenly, on one of my startups the resolution showed up. I uninstalled SwitchResX and it was still working. 3 days later it is still working and I'm keeping my fingers crossed :)

I am on macOS 12.0.1 on a 2017 13" MBP. What I did was uninstall BetterDummy. Then uninstalled the LG software for my monitor (LG 29WN600-W). Then I installed the SwitchResX trial but needed to set a custom resolution (2560x1080) and refresh rate (75 MHz) . Have set monitors up as my UltraWide as main with a 2560x1080 resolution. Have rebooted couple of times to see if the settings hold across boots and so far so good.