Disable related email highlighting in Mac Mail (conversation thread colors)

Mac Mail comes with a feature that allows you to highlight (in light blue, by default) email messages part of the same conversation thread - this is a useful way of visually identifying related topics at a glance but, depending on how you use Apple Mail, could well become something of a nuisance. In this tutorial, we will show you how to turn off email highlighting in Mac OS X, and keep all messages with the same default white background color.

Prevent Mac Mail from highlighting related emails

• Once inside your email program, access the "Preferences" under the "Mail" menu.
• Then, click on the Viewing tab at the top of the dialog that opened.
• At the very bottom of that tab, you'll see a section labeled "Message threading" , with two settings - if you wanted to change the color Mac Mail uses to highlight related messages in a conversation thread, just click on the color swatch button as shown on the screenshot below, and pick a different color:
  
  
• To turn off background color highlighting altogether, just uncheck the "Highlight related messages using color" checkbox. Once you have, just close the Preferences dialog and click "Save" to apply the new setting.
• From this point on, Apple Mail will no longer color conversation threads, regardless of the grouping and sorting options you have picked from View menu (even if you select "Organize by Thread" from it).

This is how easily you can turn off email messages background coloring in Mac Mail; you can at any point follow the same steps explained above if you change your mind and decide to take advantage of the feature after all. Unlike other features, this one is turned On or Off application-wide, not an email account by email account basis.