I have an Dell external display which has the best resolution @1440*900.

My laptop is 2015 13 inch rBMP MX840. The problem is that when I connected this external display into the Mac, it cannot show correct resolution, it only shows some general old 4:3 ratio resolution such as 1280*1024 etc. enter image description here

I tried to use a utility called Display Menu but I still cannot see the optimised resolution. Here I post one screenshot of all resolution shown in that tool.

enter image description here

Any idea to solve that issue? The correct resolution can be shown when I use my old MBP which comes with a non-retina display. By the way, I am not using Apple official Thunderbolt-VGA converter.

  • I’ve got a similar problem with an old Belinea SXGA monitor. OS X 10.11 offers only 4:3 resolutions (e.g. 1280 × 960, defaulting to 1024 × 768), when the screen actually has an aspect ratio of 5:4 (1280 × 1024). Your screenshot reassures me that Apple does support its native resolution, but somehow can’t select it.
    – Crissov
    Dec 19, 2016 at 11:48
  • Holding alt / opt / ⌥ while selecting 🔘 Scaled did the trick for me.
    – Crissov
    Dec 19, 2016 at 12:00


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