I have an iMac Retina 5k 27", late 2015 and I also have Dell monitor which supports VGA, HDMI,and DVI inputs. I want a dual monitor setup by using this Dell monitor as the second monitor.

My question is how can i do it? Should I use a cable converter to connect it? Is there setting should I change in macOS?

I bought a DVI to Thunderbolt converter. When I tried to plug it in, I just saw a blank screen in second monitor.

Here is the specs of iMac:

  • iMac (Retina 5K, 27-inch, Late 2015)
  • Processo: r 3.2 GHz Interl Core i5
  • Memory: 8 GB 1867 MHz DDR3
  • Startup: Disk Macintosh HD
  • Graphics: AMD Radeon R9 M380 2048 MB
  • 2
    There is countless resources that address this very topic; even from Apple themselves: support.apple.com/en-us/HT202351 Also what adapter are you using? It's hard to diagnose the problem when we're missing key details.
    – Allan
    Mar 14, 2018 at 13:11

1 Answer 1


You will find in System Preferences a control panel where you can set and control where menus appear etc.

Also, you can set the mirroring options to appear in the menu bar as necessary.

Personally, I would purchase adaptors to go for the HDMI input to the second monitor.


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