2 identical screens are exchanged

I have a permanent installation with Mac mini M1, and 2 projectors, with 2 different signals, the projectors are of the same brand and model, at the beginning of the day the client turns it on and sometimes the screens are exchanged, I think the problem it's MacOS, it sees both projectors with the same name, OS just changes the number and I think sometimes it doesn't know which is the right number and swaps the screens. To try to fix this, first the projectors are always turned on and then the MAC mini, the project opens by default with the OS in full screen, I also tried with an HDMI Dummy, so that it recognizes 2 different outputs with different names, but Sometimes it happens that it stays on a black screen as if the mac mini was not sending it a signal. Is there a way to force the OS to change the name of the ports or target the video output to the hdmi 1 connector (as Watchout does) and not to the projector model?



  • Hello @pierolr,

    Could you try with latest beta version ?

    Best. Philippe

  • Hi,

    I will try and tell you.


  • Hi, I still had the same problems, I finally solved it by placing a splitter, with it the output was recognized with another name and it no longer exchanged the signal, it would be good to add an option to fix the output to a physical connector and not an output name by when you have several units of the same model.


  • Hello @pierolr,

    This does not depend on Millumin (nor us) but on macOS. Unfortenatly, the ID produced by macOS tends to change after a reboot. We do our best to distinguish the outputs, but sometimes this is not possible.

    Of course, feel free to reach us via email, so we could dig this futher (I mean with special tools).

    Best. Philippe

  • Hi Pieroir,

    Could you explain more your solution ?

    Does u put 1 splitter on 1 output, and the other output directly or

    1 splitter on each output ?

    What type of splitter did you use ?

    Thanks a lot

  • Hi Boris,

    yes, I put 1 splitter on 1 output, and the other output directly .

    It´s a very basic and cheapper chinese splitter 4k.

    Best, Piero

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