Mail sorts from oldest to newest by default
This design choice escapes me and is highly annoying. Go go Preferences/Settings > Config Editor (the very bottom problem at the page)
![](https://wonghoi.humgar.com/blog/wp-content/uploads/2022/02/image-5.png)
It’s called Advanced Preferences tab. Look up mailnews.default_sort_order and change the value from 1 (ascending) to 2 (descending).
![](https://wonghoi.humgar.com/blog/wp-content/uploads/2023/05/image.png)
You can change the field to sort by mailnews.default_sort_type. By default it’s 18 (sort by date)
Thanks https://markohoven.com/2021/01/06/descending-sort-order-thunderbird/ for the clue.