Ah, NOW it let's me add images. Please help. Searching the forum it appears I need to disable the 'conversations' but can't find instructions on how to do it so I can see whether or not that fixes all the problems.

Oops - 'correspondents' not 'conversations'

Correspondents is a column just like any other column. At the far right end of the column headers is a small icon. Click that and turn on or off any column you like.

The forum seems to be finicky about adding images to the original post. No one seems interested in fixing that.

Thanks, Airmail! Any idea how to fix the issue of not being able to see email content?

Restart Thunderbird is safe mode by holding shift when opening. You may have an add on causing issues.

Nope. Didn't help :-(

I see you are on a MAC. There have been a few threads about displays issues on MAC with v45. I do not remember seeing any of them with solutions or with proof that is the issue. I wish I had something for you. In the mean time you could go back to v38 and let the bugs in 45 get sorted out. I usually wait a few weeks before making the upgrades. I did it early this time due to all the questions and have had good luck so far on Windows 7.

Ah. Not being too tech savvy, can you ELI5 how to revert to v38? Sorry to be a noob.

Before you do that I found this thread about issues with Conversations and Lightning. Maybe that will help. https://support.mozilla.org/en-US/questions/1119805

Nope. Still can't see the content of any of my email.