Do you have files like prefs-1.js, prefs-2.js, prefs-3.js.... in the profile folder? If so, rename prefs.js to prefs.old (with TB closed), rename the newest prefs-N.js to prefs.js, restart TB, and see if the setup is recovered.

https://support.mozilla.org/en-US/questions/1360261

I have 1 file called prefs says it is a java script file. When I double click on the file name I get a Windows Script Host box. It show the full script but there is no place to change the prefs.js. Which is at the end of the script. I can not find any prefs-1 files.

I changed my preferences to allow hidden files. the full prefs.js showed up. I changed it to prefs.old.

I restarted my computer. Thunderbird program still loads blank. I did a complete search of my computer and found another prefs.js file in a different Thunderbird profile folder. I changed that file to prefs.old and restared my computer.

A new prefs.js file showed up in the second profile. So I now have a prefs.js file and a prefs.old file. And the Thunderbird program still loads blank.

I did not file any prefs-1 files in my computer search.

If the prefs.js in the current profile is missing the account details (open the js file in a text editor such as Notepad), and there are no prefs-N.js files, you can try replacing the damaged prefs file with one from another profile or profile backup. But if none of those options are available, you will have to add your accounts. It will probably be possible to recover 'lost' data such as local mail and address books.

Doing regular profile backups or just backups of critical parts will prevent issues in the future.

I have no idea what you are talking about. I am not a "computer" person. I have used Thunderbird since it started and this is first time I have had any problems. Are you telling me my emails are gone?