Hi. I’ve made all that SwitchRes standard procedure and the CAC-1170 worked fine at 4K 60Hz with my LG 49UH6500 and my Macbook Pro Retina 15 mid-2015. And then… I played a little with the “scaled” feature in Mac OS Sierra display settings and after two or three scale changes it stopped working. Now all I get is a black screen. Tried deleting the custom resolution I had set up in SwitchRes, then rebooting and then setting it all up again, but still nothing.