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My mac pro with dual monitors keep switching sides after reboot

Hi all,


I am having a really weird issues with my Mac Pro after I installed Mountain Lion. I have dual ACD Monitors. Every time I reboot, the monitors switch sides. In other words, the monitor that is in front of me with the dock would switch to the other monitor and vice versa after I reboot. When I reboot again, it switches back again. This is extremely annoying. I have had to switch the inputs on the back of my computer every time.

Mac Pro, OS X Mountain Lion (10.8.2)

Posted on Nov 21, 2012 4:54 PM

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17 replies

Feb 14, 2013 5:43 PM in response to Neeper78

I think I have found a solution to this pesky problem...


I believe the reason this problem is happening is because both monitors are using the same color profile.


GO to: System Prefs/Display/Color and take a look at the profiles for each monitor. If they are set to the same profile, that's your problem right there.


By simply setting them to different profiles, I got rid of the dual monitor-switching problem at reboot.


Try it, and let me know if it works for you as well...if so, I'll have to congratulate myself ...for the first ever technical contribution I've made to others on the internet!!


Cheers!

Link6009

Feb 14, 2013 11:53 PM in response to link6009

Wow, I think you may have solved it!!! So far so good for me after a few restarts. The first time I restarted it, it switched again. So I checked to see if the cables were reversed from when it used to be normal, and it was. Now everything seems to be normal.


Let me be the second person to congratulate you! Thanks for solving this annoying nusance.

Feb 25, 2013 1:35 AM in response to Neeper78

I hate to burst my own bubble here, but I recently added a 3rd monitor, and now I'm getting the same inconsistent monitor switching between my second and third monitors.


Here's my set up:


Mac Pro, OSX 10.8.2

2x2.26 GHz Quad Core Intel Xeon

16 GB RAM


Three Dell ST2420L display monitors


What seems to be happening now is that I get three identical 'color' display profiles. The first one seems to stay on the same monitor, but the second and third monitors now switch at random. I can't seem to get them to stay in any particular order.


Any suggestions or new approaches for solving this would be greatly appreciated!

User uploaded file

Oct 10, 2013 3:26 AM in response to Neeper78

I had similar issue and realized that i had several profiles that i do not use.

After deleting them from the library (You can see the path when u hover over it), and leaving only the two needed by the actual displays, it stopped switching.


The issue it had in particular: it switched during normal workload, without rebooting.


Also, you can check the settings to display only the profiles that are needed.


Oh and last, i did save the profiles before i deleted them...

Dec 11, 2013 2:12 PM in response to Neeper78

Ok, so I had a similar problem on Mavericks OS, apparently it handles dual monitors slightly differently...


So, I went to System Preferences>Mission Control and unchecked the box that says 'Displays have seperate Spaces' (Last in the check boxes list).


I have rebooted a couple of times now and everything appears as it should be.


Hopefully this helps. 😝


Cheers.


Tim

My mac pro with dual monitors keep switching sides after reboot

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