Here is the info of my laptop:
- MacBook Pro (Retina, 13-inch, Early 2015)
- 3.1 GHz Intel Core i7
- 16 GB 1867 MHz DDR3
- Intel Iris Graphics 6100 1536 MB
- macOS High Sierra version 10.13.4 - Acer G236HL Bbd 23-Inch Screen LED-Lit Monitor

I've tried both a SMC reset and NVRAM reset and nothing worked for me. I am so frustrated with this issue.

How do I troubleshoot this issue:

  • I used the same Thunderbolt cable and a new MacBook Pro and connected to TV - WORKED
  • I connected the Cable and my Acer monitor with OLD MacBook Pro 2012 - WORKED
  • I connected the MacBook Pro 2015 and same cable and Acer monitor - Not working.

That means the port is working fine with new MacBook Pro.
Cable is working fine.
Monitor is working fine.

The big issue is not being able to detect the display on the MacBook Pro 2015.

I'm not sure what else I need to do.
Does anyone have a solution for this issue?

I tried calling Apple Customer Service and they are clueless.


1 Answer 1


If the external screen is flickering and blacking out after 3-5 sec, try going into System Preferences > Displays and change the settings for your external monitor. I solved mine by setting the Resolution to 1080p and Refresh rate to 60 Hertz.

P.S. You can bring the display settings window of the monitor to your main display on the Mac by hitting 'Gather Windows'.

  • The above response worked. For some reason, changing Refresh rate solved this issue entirely! Be sure to try it. Dec 9, 2022 at 15:15

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