Thunderbird is my favorite e-mail client. But one thing that always bugs me is after a new install the e-mails are sorted from oldest to newest. You can change that but Thunderbird will not remember how you had it set when you close the program and open it back up.

That sort order may be better for some people but I’m not a big fan of it. And there is no way to permanently change it in the GUI. So we have to go into the advanced settings to fix it.
How To Change Thunderbird’s Sort Order
Go to the Tools menu on the top then to options. You might have to push “Alt” to get the menu to pop up.

Linux: In Linux click the 3 line hamburger icon on the right. Then Preferences then advanced.
Then on the next page make sure you are on the General Tab then go to the Config Editor button on the bottom right.

Next you will get a warning. You have to accept it to continue.

Now on the next page type “default_sort” in the search box. You should see a value called “mailnews.default_sort_order“. Change the Value of this to 2 and that will tell Thunderbird to start sorting your e-mail from newest to oldest (Descending). Or if you wanted to go back a value of 1 will sort mail from oldest to newest (Ascending).

The default sort type with the value of 18 tells Thunderbird to sort by date. So I just leave that alone. But if you want to learn more about that you can see what is available from Mozilla’s documents. The values on that site are in hex so you will have to convert them to decimal.
All Done!
Now when you close Thunderbird and open it back up it will have the sort order you prefer!
I hope this has helped and happy e-mailing!
Not quite enough info. This does change the default sort, but when you open a folder it still jumps to the very last item in the list of emails. Obviously in a date descending sort you want to jump to the first item in the list.
I’m sorry. I’ve never seen this issue. Maybe it’s remembering where you left off and it’s jumping down to that e-mail? I’m seeing that happen on mine when I look at my big archive folder. So that would be my best guess without knowing more details.