Unless you have a backup prior to installing the upgrade that made all of these changes, it might not be possible. If you can, restore your old Thunderbird install and prevent the app from updating. Thunderbird is changing things so fast, so often, and breaking things with every update it has me searching for a new solution.

Go to Help > Troubleshooting > about:profiles

Is more than one profile name listed?

Wayne, Please read my original post asking for help. I have no idea what you are telling me. I found my profile, though it is huge and foreign to me, I have no idea what to do with it. Any advice for an 83 year old user, not tech savvy? In plain english please.

TB78 email program collects emails, but does not allow send an email. (????) What good is it?

What about the second part of my request? Changing the front page color from white to yellow?

One thing at a time please. Just the names.

1. In Thunderbird

* click help
* click troubleshooting
* click about:profiles (near bottom of first section named "Application Basics"

* what profile names do you see listed? "Profile: <name>

2. But since you found a profile, what is the name of that profile?

This screen shot is an example

Profile: default

Profile: Shell profile

Profile: default Profile: Shell profile

Thanks

Which of those two profiles is indicated as being "in use" (meaning the one your are currently running)? And this is the one that doesn't have all your address books, correct?

And what do you see for address books if you switch to the other profile by clicking "set as default profile" and restarting thunderbird?

Thank you very much, I now have my address book back and so I can send emails.

May I ask you to now address the second part of my original question involving changing colors.

" I had custom colors for the main display page of new emails (which is not white).  White is hard on my eyes and difficult to read from."  

How do I change the color from white to yellow on the page all the new emails display each day?

Please reply, waiting since 11/20/20.

I had custom colors for the main display page of new emails (which is not white). White is hard on my eyes and difficult to read from.How do I change the color from white to yellow on the page all the new emails display each day?

This is the original question asked 11/20/20. Still remains not answered. I would appreciate some help.