Ventura : profile issue with external monitor

[fctx]

Hi,

Not really sure on how to adress this issue appeared couple of days before but, to make it short:

Situation:
MBPM1 Ventura;
2 external displays ( LG 27' Ultrafine 5K IPS - Only for Mac);
Both connected TB4 from ther MBP (No adapter nor other things);
In day2day usage, MBP is closed and I use only one External ( let's called it LG1) then LG2 is unplugged from ther MBP

past behaviour
I boot, get the login screen, fill in credential, short shutdown ( less than an half sec) of the screen (LG1) and then I'm in my session with my regular profile ( let's call it Prof1)
Depending the job I do, I connect LG2 ( plug the TB4 into the MBP): no issue, works perfectally (except a background noise in my Berhinger HP ( don't know why .. but it is not the subject of the day ;-) )

Today Behaviour
I made a change in screen definition and from that moment, LG1 refuse to work if LG2 is not connected at the same time;
When I reboot with LG1 only, the login screen appear normally, I can fill in the credential, short shutdown (as above) but display remain black; if I connect LG2, both monitors switch On and works fine;
If I disconnect LG1, LG2 continue to works;
If I disconnect LG2, LG1 stop to work.
I've made a lot of tests ( switching the cable, switching between MBP ports, switching the monitors ) still same results;
But the more intersting one was that everything working well when I log with another profile (Prof2).



My conclusion
Issue reside somewhere into my Prof1.
But where? and Why? and finally, how to resolve?

Many thanks for your help, have a nice day from here ;-)

FRED•ERIC

 

[Brian33]

You have done some very good troubleshooting and described the problem well. I agree with your conclusion, that the issue has to do with what you call your "profile" Prof1 (but others may call a user account).

I made a change in screen definition and from that moment, LG1 refuse to work if LG2 is not connected at the same time

I assume when you made the change you were logged in as Prof1. Did you make the change in System Settings? In Displays? (Or whatever it's called in Ventura; I'm still on Monterey and I know that some system preferences/settings got renamed or moved.) More details here might help someone else suggest a solution.

Since you seem to have narrowed the issue to one particular profile (user account), here's one idea:

Many (but not all?) of these settings (or speaking the old way, "preferences") are stored in "plist" files in '/Users/Prof1/Library/Preferences'. (Each user account would have its own versions of these files). Often these '.plist' files can be deleted (or moved) and they will be re-created. You'll lose any customization you've made that is kept in that file, but you should be back to the default settings.

Log into your Prof1 account. In Finder, the 'Library' folder is hidden by default. I think pressing Shift-Command-L or using the "Go" menu will get you there. From there you can get to Preferences. But I don't know which particular '.plist' file the Display settings might be in. You could try sorting by date/time. It should be one of the "com.apple...." ones, but there are a lot of them! I was hoping to see 'com.apple.displays.plist' or similar, but no such file on my Monterey system...

If you find one that seems likely to contain the Display setting you changed, you can move the '.plist' file to your Desktop for safekeeping. You might need to go into System Settings/Displays again without changing anything, or maybe not. In any case, usually the '.plist' file will be re-created with default values.

Then see if your monitor issue remains. If it didn't help, you can replace it with the one you saved on your Desktop.

Good luck.