You weren't specific in your attempts. Did you try help>moretroubleshootinginformation, scrolling down to 'Profiles' and then selecting 'about:profiles' and then clicking 'create profile' to select yours?

I figured out how to show hidden files on the thunderbird browse function. I feel pretty stupid about that. However, when I select the appropriate file, I still get the same error message:

The Local Directory path "/home/tony/.thunderbird/r7alciqv.default-release/ImapMail/mail.myemailserver" is not suitable for message storage. Please choose another directory.

Same message for my gmail and yahoo accounts.

I can send messages, but cannot receive email or sync accounts. I can see all my email folders in the above above folder, but the application will not select the directory. The app hangs on saving to the "sent" folder and the "draft" folder after sending a message. This is also related to the issue of not being able to select the appropriate directory.

Also, it will not create an account for a second gmail account. I saw another poster in the forum with the same issue. It created one account (although it's not receiving/syncing), but after authorizing Thunderbird in Google for the second account, the second account does not show up in Thunderbird.

I use Thunderbird in Arch Linux and have no problems, but this installation in NomadBSD (based on FreeBSD 13.1) will not work, so I am assuming this is a FreeBSD-related issue. I have spoken to others with similar issues, but nobody has a solution yet.

If you think you can help, let me know what information you need and I'll provide it.

OK. I found the "more troubleshooting.." under the help menu.

Under "Profile Folder" -> "Open Directory" it opens the correct directory. Under "Profiles" it shows the correct directory and profile information for my accounts (less the second gmail account.)

I don't know what a lot of the information shown under the other headings means, but I saw nothing that looked amiss to me.

I tried restarting under secure mode (all addons turned off) with no joy.

I am unfamiliar with BSD, unfortunately. I hope someone else sees this thread for you.

SOLVED:

This was indeed a NomadBSD problem. NomadBSD is a live USB OS that can optionally be installed on the computer's SSD/HDD. I configured Thunderbird while it was running from the USB stick. When I migrated it to the SSD, the home folder moved from /data/home to /home and Thunderbird was still looking for its configuration files under /data/home/username/.thunderbird.

The solution was to uninstall Thunderbird, delete the /home/usersname/.thunderbird directory and subfiles, then reinstall and reconfigure Thunderbird. It's working like it should now.

Maybe somebody else will profit from this.