Force RGB Mode in Mac OS X to Fix External Monitor Picture Quality


Lot of Mac OS X users reported this issue. When they try to connect MacBook Pro with Retina screen with Dell U2410 monitor using HDMI cable, they getting poor picture quality, wrong contrast and irregular text display.

Reason for this issue:-

Mac OS X things your monitor is a Television and using YCbCr colour space instead of RGB.

Solution:-

You need to override EDID settings to force the RGB colour space. It will fix the issue.

Force RGB in Mac OS X El Capitan

This steps will  force RGB in Mac OS X 10.11 El Capitan. If you have different version of Mac OS X see below for earlier versions.

  1. First download Andrew Daugherity’s patch-edid.rb script from his github page. Put this script in your Mac Home directory.
  2. Then disable “rootless” mode (Use Mac world.com article).
  3. Restart your computer.
  4. Only connect external monitor in question, if its possible (ex: Close the MacBook Pro lid). patch-edid.rb script will override files for connected monitor.
  5. Open Terminal.app from /Applications/Utilities/ folder and type the following command
    ruby patch-edid.rb
  6. It will create new folder in Mac  home directory. Move the folder into “/System/Library/Displays/Contents/Resources/Overrides” folder. If the Mac warn you that you are overwriting an existing folder, first try to backup the folder.
  7. Reboot your MacBook. It will fix the picture quality.
  8. Now Re-enable “rootless” mode (Use Mac world.com article).
  9. Restart your computer. Thats all.

Note: If you need to undo the changes, delete the folder you had copied to Overrides folder or replace it with backup. Mac requires to re-enable rootless mode to do this step.

SEE ALSO : MacBook Pro does not detect external monitor display, fix

Force RGB in Earlier version of Mac OS X (Yosemite or Mavericks)

The steps are little more straightforward. There are 2 differences to the steps (for El Capitan) above:

  1. Don’t need to disable and re-enable rootless mode & perform subsequent system restarts.
  2. Overrides folder location : /System/Library/Displays/Overrides.
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