When I first changed the black toner, the light just kept blinking. I would install an old Xerox brand toner and it would register it. Then I took out the blue toner and put in the non-original one, it registered it as NON and worked. I tried again with black, same thing only the lights were blinking. I took it out and put it back in, finally registered as NON and it worked. Prints beautifully, I was worried it wasn't Xerox that it wouldn't work, but it works. Be patient.