Yesterday I updated to Thunderbird v. 102.13.0. This morning, when I launched it, absolutely nothing was in it. I had 4 accounts set up. Two have been inactive but I wanted to retain those emails and folders. My primary account (an Outlook one) was easy enough to re-connect, though all of my address books and saved addresses have been lost. The fourth account will probably be lost forever as I can no longer access it.

How could this have happened? Is everything definitely lost forever? I have been using Thunderbird for decades and nothing like this has ever happened to me.