FVAi inspection reverse image

I autofocus, with my FVAi inspection microscope, but it cannot find the fiber and all I see is a bright white circle on a black background.

When you see a bright white circle on a black background (the reverse of a normal inspection image of a fiber end) then the microscope is so far out of focus that you are seeing the aperture of the microscope and not the fiber interface. You will need to perform a significant manual adjustment to bring the fiber into view. Once manually adjusted, the autofocus should then be able to focus the fiber.