Open by default your inbox or any mailbox upon Thunderbird start, with this addon
As you may have noticed, when Thunderbird starts, it opens the last used mailbox, guessing that next time you prefer to see first this mailbox to continue your work. Nothing wrong in guessing, but freedom of choice is better, and Thunderbird won’t let you change this feature — no option in the settings.
As with so many things, a Thunderbird addon provides the solution. The addon is called Manually Sort Folders, and besides what its name says, it will also let you start Thunderbird making any mail folder default. I use this addon to open by default the Inbox, but you might need some other mailbox even more.
Note that the official version of this addon is not compatible with the latest Thunderbird; the one I am presenting here is modified and it should be considered something like beta.
If you prefer to install only officially stable addons, just skip this. In any case, I give you also the address of the official addon at Mozilla to try it first in case it is now updated and works. Enjoy!