Connecting TWO ATEM Minis to same MacBook Pro

Hi all!

This is my first post, so please bear with me – I'm also not a native English speaker, so some of the information I'm trying to convey might be obscured by the fact

On a couple of occasions I've turned to the use of two ATEM Minis (one of them is a Mini Pro) connected to the same MacBook Pro (Intel) running the latest available macOS updates. I'm running this setup in conjunction with ProPresenter, as a means of doing live large screen production from multiple sources (3-4 live cameras and two-three external PC units running presentations) that are meant to be displayed at the same time, as well as some stage monitors.

The problem:
I've occasionally run into a disability from ProPresenter's (or macOS') side to actually differenciate between the two ATEMs, and the confusion is sometimes total when disconnecting and then reconnecting the ATEMs. It seems almost like the two units are interchangeable and that macOS/ProPresenter doesn't have any means of identifying them as unique units. The planned and premade templates in ProPresenter suddenly has the feeds switching placement, and I need to go back and remap the "opposite" units to their correct placement in the layouts.

Is it so that this "hack" isn't meant to work in the first place? Or is there something I could do in either ATEM Setup or ATEM Software Control to ensure a stable production environment? As I'm sure you can all relate to, last minute changes with the accompanying stress isn't always welcome when 250 people is sitting in the conference hall waiting for the "show" to begin...

To be clear:

• I'm not sending HDMI out from one ATEM to the other
• Both ATEMs are connected to the same computer
• They're always connected in the same position and on the same input on computer
• I'm getting this to work, it's just the stability of the setup that is somewhat "wonky"

Any insights, tips and clues is warmly welcomed!

All the best,

-Tom

I think this can be simplified to :

When I connect a single Mac via two sepaate HDMI outputs to two different Atems, in order to feed each Atem different graphics from Pro Presenter, the Mac and, thus ProPresenter, doesn't know which HDMI output is feeding which Atem as they have the same labels (It's like feeding two identical branded monitors and not knowing which is which)?

So the question is whether Atems can be labelled so their (EDID?) signalled name isn't duplicated when multiple Atems are connected to the same machine? I'm not aware that's possible.

Windows has a way of displaying a large number in each connected display to uniquely identify it (so you can arrange two duplicate displays as you want them) - but I don't MacOS has that option.

You can force display detection by Option Clicking Nightshift in System Settings->Displays.