Some like it; some don't. You can change it to your preferences. Full documentation is here: https://support.mozilla.org/en-US/kb/message-threading-thunderbird

Hi David,

Thanks for your response. I had located that document before but it doesn't clearly answer my question.

I simply want to disable Threading for all current and future folders. I can see how to do it for future folders (which is not simple or straight-forward) but I am looking for how to easily and in one place say No Thanks to Threading globally.

I agree some will like Threading and some won't. That is why I expected Mozilla to offer it as an option that users could turn ON if they wanted it, rather than have it imposed and leave users to figure out how to turn it off.

Kind regards,

Graeme

That URL is the official statement. Here is my unofficial one. (and you're not the first to not like it. Many of us were not pleased, but at least there is a fix.)

More info: To change default for *new* folders, In config editor, you can change default that applies to NEW folders you set up: mailnews.default_view_flags 0=unthreaded

Config editor is available at Tools>settings>general and scroll to bottom right.

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To set many *existing* folders, follow these steps: (I creates a crude video that walks through the steps at

   https://davidkirk.org/SettingDefaultFolderView.mp4  that demonstrates the following steps:

  First, highlight a folder that you have set to unthreaded	
  Then, In the Message List view, in the column header, on the far right, open the options button that shows    
   context menu. :
  At the very bottom is the option:
  -> "Apply current view to..."
  -> "Folder and its children..."
  -> Hover over an account
  -> In the next menu don't select a folder. Instead select the account name itself.

ALSO, for future installations of Thunderbird, - install Thunderbird and exit prior to setting up accounts - create a simple text file with name of user.js with these lines:

    // Set default threading to UNthreaded  ###   <== this line is optional, just for documentation
    user_pref("mailnews.default_view_flags", 0);

- copy the user.js file into the profile - now, when you start Thunderbird, unthreading will be the default. Problem solved.