I got the 250x microscope, installed DigitalViewer 3.1.07 on a retina MacBook Pro MacOS 10.12.3, and DV is not recognizing the camera at all. All it lists is the built-in FaceTime camera, there is no other option in the dropdown.
If I fire up Photo Booth, the microscope shows up as “USB Camera2.0” and works just fine. The microscope is also recognized on the USB 3.0 bus when I look at System Information.
EDIT: oookay, if I repeatedly open/close the DV app I can get it to recognize the microscope sometimes.
Earlier today I had DV working with the microscope on my work MacBook which is an identical configuration, but now DV doesn’t work on either laptop.
The driver page for MacOS lists 3.1.08, but the download link is really 3.1.07. Even if I copy-paste the 3.1.08 URL it still installs 3.1.07 so I don’t know if that’s expected or matters. Also the “related product/service” box on your forum post page is badly in need of some sorting.