Good news/bad news. In config editor, you can change mailnews.default_view_flags from 1(threaded) to 0(unthreaded). But that does not apply to preexisting folders, only to new folders. I filed a bug report on this, but the developers believe their changing default to threaded is the best move.

Hello. Is there a way to make SORT BY THREADED and EXPAND ALL THREADS a default? Several times during any one session, as well at start up, I have to select both SORT BY THREADED and EXPAND ALL THREADS. This is a critical failure. It is easy to miss important emails (responses). Also, the need to focus on that issue and having to repeatedly make the sorting selections is very disruptive. Thank you.

I have the same problem. It's particulary annoying that a new message in a thread doesn't mark the top message/header so I can't see that there was a reply. I now have to carefully watch my threads and that takes to much time. While I like the threads. They are very handy especially when I have to look for something we have talked about in the past.

My thought is that the 'solution' for unthreaded also applies here. That is, once one folder is set, apply the setting to all other folders. See sample: https://davidkirk.org/SettingDefaultFolderView.mp4

If you want folders threaded and expanded, I suggest trying this: - set one folder as desired. - then click the options to set remaining folders to same setting. here is a simple video to demonstrate:

   https://davidkirk.org/SettingDefaultFolderView.mp4

This does not seem to work for the View-Sortby settings. It only seems to affect which columns to display.

No, the lower option is 'apply current view..

Thanks David, I figured that out eventually - now I just need to figure out how to change the default so that new folders don't use sort by threaded! It even looks like they sometimes revert back to threaded after I change them to unthreaded

Please see top of this thread. I list an entry for config editor that sets default for new folders. I repeat part of it here: In config editor, you can change mailnews.default_view_flags from 1(threaded) to 0(unthreaded). But that does not apply to preexisting folders, only to new folders.