We have now problem with trying to work two ASI120MM cameras in same computer.
The other functions as a guide camera and the other as surveillance camera.
Machine is Intel NUC with Windows 10.
Surveillance camera works with SharpCap but then when starting to use guide camera surveillance camera doesn't show anything and SharpCap says 0 frames previewing.
Device manager tells both are connected fine.
So it used to work with native driver and just one at a time.
Tried with ASCOM drivers too - result 0 frames previewing, with native drivers - constant number of dropped frames. USB bandwidth minimum.
Please pay attention to the USB bandwidth for each camera.
Beside, please make sure that you are operating the different camera, not the same one. You know, they have the same name in the device list.
Earlier both of them worked when only one of them was available.
Now the surveillance ASI120 is connected to PC (and it doesn't work). Guide camera is connected to USB hub and i t works.
Next we try to disconnect guide camera (we don't need that much) so at least surveillance camera works (that's more important to us).
I think you might be opening the same camera.
I tested on my Win7 with 2 120MM by Sharpcap, they works well.
Maybe we can do a simple test: Upgrade the Firmware for one of you 120MM to 120MC, then test them.
After the testing , update it back.
Beside, which application do you use for the guide camera?
You think changing firmware in surveillance ASI to colour might do the trick ?
We used PHD2 for guiding (also have tried PHD2 with surveillance ASI, and also used surveillance ASI with Firecapture).