Anyone who wishes to help, I am here attaching the image that never uploaded when I posted this question originally. JasonPotter

And if you click on a folder in the left-hand pane...? Or on "Read messages"?

When I click on a folder in the left-hand pane or on "Read Messages" I get nothing new...the window presented in the screenshot I sent stays the same.

Try to start Thunderbird in safe mode and then uninstall Lightning. http://kb.mozillazine.org/Safe_mode Restart Thunderbird. Re-install Lightning if needed.

christ1: you are a lifesaver! Not only did this solve the problem with the loss of the inbox email list (which I discovered a workaround that provided a display of that email list), but two others (once I got the inbox list showing, I could no long see the tags I had created to mark different kinds of emails, and also, attachments could not be seen and clicked on, though there was *another* workaround to deal with that). All functionality seems to have been restored.

One final question: when accepting Mozilla requests to upgrade/update Thunderbird, should I first disable Lightning and then renable it?

jasonpotter said

One final question: when accepting Mozilla requests to upgrade/update Thunderbird, should I first disable Lightning and then renable it?

No and we would appreciate being told if issues like this arise into the future. This particular issue was, we thought, put to bed in the last release. But here is is large as life again.

When your problem has been fixed can you mark the thread as 'Solved' please? Thank you.