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Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Just upgraded to 11.3. The screen resolution was a bit off after the restart once installed.
I was fiddling around with the screen resolutions and accidentally chose one that messed up everything.

Now I don’t know how to get it back to normal. The screen is black except for every 10th seconds when it flashes a brief moment, not even a second. When it flashes I clearly see my desktop so that I’m logged in.
ive tried booting in to safe mode but the screen problem persists. In startup option everything runs smooth and runs as expected. As soon as the desktop/login window appears the kind of flickering begins.

Mac mini M1 16/1TB and my monitor is LG 34” LG 34WK95U-W. I have an Apple original thunderbolt connected to the monitor.

I’ve fiddled around with the monitor settings as well but with no luck.

Can’t find any articles how to downgrade to previous macOS version either ?
 

CMMChris

macrumors 6502a
Oct 28, 2019
844
791
Germany (Bavaria)
ive tried booting in to safe mode but the screen problem persists.
You get the black screen in safe mode as well or you mean changing in save mode doesn't change it for normal mode?

Can’t find any articles how to downgrade to previous macOS version either
Downgrades on Apple Silicon are only possible through Apple Configurator 2 and an old IPSW file.
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
You get the black screen in safe mode as well or you mean changing in save mode doesn't change it for normal mode?


Downgrades on Apple Silicon are only possible through Apple Configurator 2 and an old IPSW file.
The safe mode it self flickers. Currently reinstalling OS.

Just finished reinstall, the problem persists ??

Works fine with my Windows Laptop with the same cable. So I’m out of ideas
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Is there a way equivalent to Gentoo Linux "boot to terminal" and eventuality configure the equivalent to "X" in MacOS?
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Are you able to open the screen settings during the brief moments it flashes up?

No, but now I managed to get back in with a HDMI-cable, but it's a bit blurry.
Don't know how to fix this. Is there any issues with M1 and ultrawide screens?
Are there any large ultrawide monitors that's fully supported and works out of the box with these computers?
Not those Apple monitors, they are too expensive. I'm thinking of something cheep, in the prise range around $2500 or so.
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Now this is strange.

I do have a HDMI cable attached to my monitor and was thinking it found HDMI automagically, but plot twist, the monitor input is Thunderbolt.

?

Now my Mac mini is acting like I've got two monitors attached.

As soon as I disconnect my HDMI cable from the Mac mini the screen starts acting weird again.

What can I do to resolve this?
 

snorkelman

Cancelled
Oct 25, 2010
666
155
Before anything else try another thunderbolt port on the mini with monitor disconnected from HDMI- it might reenumerate the monitor as a fresh display and assign it default values as it has done when plugged in via HDMI


If that gets you no further forward then if you're really really stuck you could always try giving this a try

first: Shutdown the mini and boot into safe mode with monitor attached to mini only by the HDMI lead

How to boot into safe mode on M1 mac

then while in safe mode find following two files

~Library/Preferences/ByHost/com.apple.windowserver.displays.UUID.plist

and

Macintosh HD/Library/Preferences/com.applewindowserver.displays.plist


*please note

  • (UUID is unique identifier multiple characters/numbers in length whch wont be same from one machine to another)
  • ~Library/Preferences is Macintosh HD/Users/your-user-account-name/Library/Preferences
  • which is not the same path as Macintosh HD/Library/Preferences (which is location for system wide preferences)
Hope that makes sense!


Anyways, locate and move those two files to another location (eg on your desktop) while in safe boot

Shutdown mini again DON'T choose restart or sleep

While shutdown and powered off, unplug HDMI cable and plug in Thunderbird cable

Power the mini back up from cold with only the thunderbird cable going from it to the monitor


On the M1 macbook Air after restarting in normal mode I could go to system preferences on the dock and choose the Displays settings panel That let me change res on the M1 air inbuilt screen, and on closing the Displays panel, recreated the two plist files I'd moved elsewhere

hopefully that sort of thing will be enough to get your screen back to being driven at its defaults

If not hopefully it wont make things worse - I've tried as much of this as I could but only have an imac and an M1 macbook air with me tonight I can confirm it is at least possible to move those two files out while in Safe mode, then reboot to normal desktop

(on my machine the reboot after moving the two plists was the point I was thinking it could go horribly wrong and refuse to re-init my M1 Airs internal display, but moving/removing them had no impact on that)
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Before anything else try another thunderbolt port on the mini with monitor disconnected from HDMI- it might reenumerate the monitor as a fresh display and assign it default values as it has done when plugged in via HDMI


If that gets you no further forward then if you're really really stuck you could always try giving this a try

first: Shutdown the mini and boot into safe mode with monitor attached to mini only by the HDMI lead

How to boot into safe mode on M1 mac

then while in safe mode find following two files

~Library/Preferences/ByHost/com.apple.windowserver.displays.UUID.plist

and

Macintosh HD/Library/Preferences/com.applewindowserver.displays.plist


*please note

  • (UUID is unique identifier multiple characters/numbers in length whch wont be same from one machine to another)
  • ~Library/Preferences is Macintosh HD/Users/your-user-account-name/Library/Preferences
  • which is not the same path as Macintosh HD/Library/Preferences (which is location for system wide preferences)
Hope that makes sense!


Anyways, locate and move those two files to another location (eg on your desktop) while in safe boot

Shutdown mini again DON'T choose restart or sleep

While shutdown and powered off, unplug HDMI cable and plug in Thunderbird cable

Power the mini back up from cold with only the thunderbird cable going from it to the monitor


On the M1 macbook Air after restarting in normal mode I could go to system preferences on the dock and choose the Displays settings panel That let me change res on the M1 air inbuilt screen, and on closing the Displays panel, recreated the two plist files I'd moved elsewhere

hopefully that sort of thing will be enough to get your screen back to being driven at its defaults

If not hopefully it wont make things worse - I've tried as much of this as I could but only have an imac and an M1 macbook air with me tonight I can confirm it is at least possible to move those two files out while in Safe mode, then reboot to normal desktop

(on my machine the reboot after moving the two plists was the point I was thinking it could go horribly wrong and refuse to re-init my M1 Airs internal display, but moving/removing them had no impact on that)

Thanks! I'll try this later tonight.
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
If you have another Mac, use the Configurator 2 app to restore the M1 Mac mini. That should get you up and going in about 10 minutes. Your display should work fine afterwards.

Unfortunately I sold my MacBook the other week. But will try the suggestion in the answer above.
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Before anything else try another thunderbolt port on the mini with monitor disconnected from HDMI- it might reenumerate the monitor as a fresh display and assign it default values as it has done when plugged in via HDMI


If that gets you no further forward then if you're really really stuck you could always try giving this a try

first: Shutdown the mini and boot into safe mode with monitor attached to mini only by the HDMI lead

How to boot into safe mode on M1 mac

then while in safe mode find following two files

~Library/Preferences/ByHost/com.apple.windowserver.displays.UUID.plist

and

Macintosh HD/Library/Preferences/com.applewindowserver.displays.plist


*please note

  • (UUID is unique identifier multiple characters/numbers in length whch wont be same from one machine to another)
  • ~Library/Preferences is Macintosh HD/Users/your-user-account-name/Library/Preferences
  • which is not the same path as Macintosh HD/Library/Preferences (which is location for system wide preferences)
Hope that makes sense!


Anyways, locate and move those two files to another location (eg on your desktop) while in safe boot

Shutdown mini again DON'T choose restart or sleep

While shutdown and powered off, unplug HDMI cable and plug in Thunderbird cable

Power the mini back up from cold with only the thunderbird cable going from it to the monitor


On the M1 macbook Air after restarting in normal mode I could go to system preferences on the dock and choose the Displays settings panel That let me change res on the M1 air inbuilt screen, and on closing the Displays panel, recreated the two plist files I'd moved elsewhere

hopefully that sort of thing will be enough to get your screen back to being driven at its defaults

If not hopefully it wont make things worse - I've tried as much of this as I could but only have an imac and an M1 macbook air with me tonight I can confirm it is at least possible to move those two files out while in Safe mode, then reboot to normal desktop

(on my machine the reboot after moving the two plists was the point I was thinking it could go horribly wrong and refuse to re-init my M1 Airs internal display, but moving/removing them had no impact on that)

Thanks for the input. I reinstalled/did a factory reset. It's all good now.
 
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Melbourne Park

macrumors 6502a
Hmm ... this reminded of my wife's HP Elitebook (nice unit with a thunderbolt mini port but and also it's keyboard not only has a great action, but its Coffee Spill Proof - take NOTE Apple.

Anyway while it was almost three years old last year, she was working from home. So I rang the service guys and checked about a 32 9maybe 34) inch monitor, with very high resolution, and I wanted the monitor to be able to run her work HP notebook computer on one side of the screen and her home HP notebook on the other side, using an HDMI and a charging at the same time Thunderbolt 3 port. HP said not problem ... but it did not work. Eventually, they took the monitor back. Then, HP would not refund the money - eventually I sought legal redress and bingo - they found a department able to refund the money. I bought a Dell similar screen which was cost a bit more and it worked.

These issues are fare worse with PCS - i spent 8 hours one day with support. And the contract was for on site support too - but with Covid, that was not happening ... i reckon 22 hours were spent resolving a chip change inside the HP monitor, that they did not realise had happened, which stopped the feature I wanted. Or perhaps, they knew all along that their advertised feature didn't work.

Still - that HP keyboard being nice and vitally, it will take a water / coffee etc. spill - makes me tempted to get a pc notebook when I get sick of my somewhat flimsy 15.4" too thin MacBook Pro 2017. its casing is bendy on its edges and its got dings on its edges (done on the day I got it when it slipped onto stone floor), the 'A" letter is now a white smudge, the left speaker crackles, but besides that, its good ...
 

Dockland

macrumors 6502a
Original poster
Feb 26, 2021
957
8,791
Sweden
Hmm ... this reminded of my wife's HP Elitebook (nice unit with a thunderbolt mini port but and also it's keyboard not only has a great action, but its Coffee Spill Proof - take NOTE Apple.

Anyway while it was almost three years old last year, she was working from home. So I rang the service guys and checked about a 32 9maybe 34) inch monitor, with very high resolution, and I wanted the monitor to be able to run her work HP notebook computer on one side of the screen and her home HP notebook on the other side, using an HDMI and a charging at the same time Thunderbolt 3 port. HP said not problem ... but it did not work. Eventually, they took the monitor back. Then, HP would not refund the money - eventually I sought legal redress and bingo - they found a department able to refund the money. I bought a Dell similar screen which was cost a bit more and it worked.

These issues are fare worse with PCS - i spent 8 hours one day with support. And the contract was for on site support too - but with Covid, that was not happening ... i reckon 22 hours were spent resolving a chip change inside the HP monitor, that they did not realise had happened, which stopped the feature I wanted. Or perhaps, they knew all along that their advertised feature didn't work.

Still - that HP keyboard being nice and vitally, it will take a water / coffee etc. spill - makes me tempted to get a pc notebook when I get sick of my somewhat flimsy 15.4" too thin MacBook Pro 2017. its casing is bendy on its edges and its got dings on its edges (done on the day I got it when it slipped onto stone floor), the 'A" letter is now a white smudge, the left speaker crackles, but besides that, its good ...

I don't understand why Apple doesn't have a list with fully compatible monitors from like 21" and up.
 

Melbourne Park

macrumors 6502a
I don't understand why Apple doesn't have a list with fully compatible monitors from like 21" and up.

With my wife's case, HP's notebook was not fully compatible with their own monitor - it did not provide a split screen capability, with two computers connected, as they had advertised, and as their support personnel thought should be available. I found my MacBook Pro 15.4" 2017 also did not allow a split screen function either, as promised by HP (who made the monitor). So ... what chance would Apple have if they provided such a list, when makers promise a feature, and it does not get delivered?

Instead, the screen makers say whether they are compatible, and if not, one can always ask them.
 
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