When no monitor is detected, macOS disables Open GL and there is no way to prevent that. As some of our software require Open GL to be active, having Open GL deactivated can lead to some issues.
But here are a few different solutions if you are using a "headless" Mac mini and you want to keep Open GL active even if no monitor is connected and to make your Mac thinks that there is a monitor connected.
The general idea goes around the idea of EDID emulation. If your Mac receives an EDID info from one of its connector, it will think that there is a monitor connected there.
Note that the information below is not extensive, you may find other solutions around, and we do not guarantee that everything will work flawlessly. We always recommend that you do your own testing with a DEMO version of your Softron software. Also, ask your Softron reseller who will be able to help you choose the best solution.
If you have multiple Computers
The best is to use a KVM that will store the EDID in order to still send the EDID to your Mac, even if this is not the computer currently used by the KVM.
There are some inexpensive ones from Aten that some of our users have reported success with. You can choose between the HDMI and DVI models. Note that when making your choice the model MUST have the Video DynaSync™ technology (have a look in the feature section) as this is the feature that will maintain the EDID. Note that the Mini Display Port model does not have that technology.
If you have just one Computer
Then a KVM may be overkill, you might be able to use a simple EDID emulator. There are multiple choices around, depending on what type of connector you want to use. Below are some examples with some links (click on the name):
- "DVI-Detective" from Gefen
- "fitHeadless" from fit
- "Headless Mac Video Accelerator" from NewerTech
- "VGA EDID Emulator 2A-130G" from Aten
- "DVI EDID Emulator" from Kramer
- "EDID Emulators" (various connectors) from Kramer Electronics
Finally, if you use an adapter to get to VGA, you can use a "good old trick". If you connect the VGA connector pin 11 to pin 5 with a piece of wire, the VGA card gets the colour monitor ID. Note this trick did not work with all the configurations.