Mac Mini - dual monitor does not keep arrangement after reboot

[nigelbb]

I have two identical Viewsonic 1920x1080 screens on my new Mac Mini M1. One is connected by HDMI & the other via a Thunderbolt 3 -> HDMI cable. I set up the arrangement to my liking with the dock on the left but if I reboot the monitors are randomly assigned to left or right so I need to rearrange the monitors to get the arrangement correct again. It doesn't appear to be a hardware ie it's not consistently HDMI on right & Thunderbolt on left as after a reboot the one that was previously physically on the left is now on the right & vice versa as far as macOS is concerned.

It's a minor thing but an irritation. Has anyone else encountered the same problem?

macOS Big Sur 11.4
Mac Mini 8G/256GB

 

[nigelbb]

Is nobody else using dual monitors with the new Mac Mini or not rebooting it?

I have solved my problem by replacing the two Viewsonic 1920x1080 screens with a single Dell 43" 3840x2160 monitor that I found for a really good price on eBay.

 

[1200K]

I have two identical Viewsonic 1920x1080 screens on my new Mac Mini M1. One is connected by HDMI & the other via a Thunderbolt 3 -> HDMI cable. I set up the arrangement to my liking with the dock on the left but if I reboot the monitors are randomly assigned to left or right so I need to rearrange the monitors to get the arrangement correct again. It doesn't appear to be a hardware ie it's not consistently HDMI on right & Thunderbolt on left as after a reboot the one that was previously physically on the left is now on the right & vice versa as far as macOS is concerned.

It's a minor thing but an irritation. Has anyone else encountered the same problem?

macOS Big Sur 11.4
Mac Mini 8G/256GB

Same issue here. Non-identical screens, one in landscape mode and the other in portrait. An irritation for sure.

 

[colinsky]

Different problem here. 16/512 m1 Mini, two identical Dell 2560x1440 monitors on each side of an UltraFine 5K. No monitor re-arrangement on startup, but all the windows in all the monitors are dumped into the center monitor upon restart or waking from sleep.

 

[bobkster]

M1 Mini, 2 identical monitors. Positioning and doc location is intermittently swapped after boot or sleep. Tried displayplacer to workaround - recorded the command line for the order I wanted, but found that the issue appears to be that the Mac's Display ID for each monitor is intermittently being switched between the two monitors. Thus, my workaround was also intermittent.

My solution was to use displayplacer to reorder the displays, driven by a Python script that:
- gets current displayplacer command line (displayplacer list) and display order/config
- swaps the order of the two displays, and
- fixes the origin values based on screen resolution data in the displayplacer command line.
I then used automator to set it up as a service, and keyboard shortcuts to allow me to call it at any time.

If anyone wants the code, I'm happy to share it.

 

[Big Jobs]

Fixed it by deleting the


~/Library/Preferences/ByHost/com.apple.windowserver.[UUID].plist

yo!

 

[bobkster]

I had tried that as well, before installing displayplacer. If this worked for you, then there must be multiple causes with the same symptoms.

Also, I have a non-mac keyboard, so any nvm reset was off the table for me (I assume karabiner is not awake until after boot).