MBP 15 (Mid 2014) 4k external resolutions gone after High Sierra update?
I finally updated my MacBook Pro (Retina, 15-inch, Mid 2014) to High Sierra, specifically 10.13.3 (17D102). After doing that my 4k external display (a Samsung U28E590 ) won't go past 2560x1440@60Hz. The display is capable of 3840 X 2160 Resolution (UHD) @ 60Hz so long as it is connected via DisplayPort, which it is. I haven't actually changed anything physical about my rig - same cables, same ports, etc. I have tried other non-HighSierra machines and they still drive the display in 4K just fine.
Anyone know how to get 4k back?