Change the default sorting order in Thunderbird

Thunderbird (2.something here as 3 is still not stable and had some nasty bugs last I tried) sorts mails by date by default. This is fine, however, it sorts them so that the newest ones are at the bottom of the list, which ... is not fine. Since Thunderbird saves its sort settings on a per-folder basis (and I have many folders) I regularly run into folders I've rarely or never been in which still have the old sorting order.

Is there any way to globally change the default sorting order to "Threads, newest messages at the top" (or anything else, which, I assume might be possible as well then)?

Answer

Open the Config Editor from the following menu options:

Tools > Options > Advanced > General > Config Editor

Or if you are using an older version of Thunderbird:

Preferences > Advanced > General > Config Editor

Type mailnews.default in the Filter bar to bring up a small list of preferences to configure. It will display similar to below:

Preference Name                      Status       Type        Value
mailnews.default_news_sort_order:    default      integer     x
mailnews.default_news_sort_type:     default      integer     y
mailnews.default_sort_order:         default      integer     x
mailnews.default_sort_type:          default      integer     y

In the above, replace the x and y of the value by double-clicking the name of the preference and replacing it with one of the following values as required:

x (see https://developer.mozilla.org/en/nsMsgViewSortOrder)

1 = Ascending
2 = Descending

y (see https://developer.mozilla.org/en/nsMsgViewSortType)

17 = None
18 = Date
19 = Subject
20 = Author
21 = ID (Order Received)
22 = Thread
23 = Priority
24 = Status
25 = Size
26 = Flagged
27 = Unread
28 = Recipient
29 = Location
30 = Label
31 = Junk Status
32 = Attachments
33 = Account
34 = Custom
35 = Received

So if you wanted to sort all mail by Thread, Descending (newest at top), the preferences in the config editor will look like this:

mailnews.default_sort_order:    default     integer      2
mailnews.default_sort_type:     default     integer     22

There are also default_(news_)view_flags settings (for mail and news), which allow to turn on the "Threaded" flag:

view_flags -- the second group of values can be added to one of the first group to combine effects, with several limitations:
  Unthreaded       0
  Threaded         1
  Grouped         64  [mail only (?)]

  ShowIgnored      8  [news only]
  ShowUnreadOnly  16
  ShowExpanded    32  [doesn't seem to work]
ShowUnreadOnly will check the View|Threads|Unread menu; this will cause only
unread items to be seen, but doesn't force a threaded view.

(See also: https://bugzil.la/86845#c74)