Rhino graphics have gone crazy after Windows security update

Hi - My office just rolled out a critical Windows security update and subseqently Rhino 7 screen graphics have gone crazy. Have reinstalled, rebooted, updated graphics card driver, etc. all to no avail. Is this a known issue and is there a fix? Am attaching a screen shot showing bizarre color gradations with surfaces with transparent materials.

Either your working display mode has changed to a gradient background, or your have GradientBackground turned on.

If you see this in on file, it’s the latter.
If you see this in all files using that working display mode on that computer, it’s the former.