First, Thunderbird updates automatically ONLY because you left the default setting. You can change that. Try:

   Exit Thunderbird if running.
   click windows key and 'r' key
   Enter: thunderbird.exe -P --allow-downgrade
   click on 'OK'

Did not solve my problem. Thank you, David. But after I do what you suggest, a coach comes up with various options, such as "create profile," "rename profile," and "delete profile." Also, below the big box are boxes to check: "work offline," "use selected profile without asking at startup." Other options are "start Thunderbird" and "exit." Given that my objective is either to fix the problem I'm having with how Thunderbird displays my emails, or perhaps to re-update Thunderbird, what do I do when this coach comes up?

Michael

Did not solve my problem. Thank you, David. But after I do what you suggest, a coach comes up with various options, such as "create profile," "rename profile," and "delete profile." Also, below the big box are boxes to check: "work offline," "use selected profile without asking at startup." Other options are "start Thunderbird" and "exit." Given that my objective is either to fix the problem I'm having with how Thunderbird displays my emails, or perhaps to re-update Thunderbird, what do I do when this coach comes up? Michael

The 'thunderbird.exe -P' invokes the Profile Manager to open and that is what you are seeing. It allows people to view a particular profile,if they have more than one and it also create a new one, but I doubt that is the case with you.

The part that says --allow-downgrade means if you had uninstalled Thunderbird and wanted to go back to a previous version, it should allow this to occur. But I'm not so sure you are asking to revert to another version.

re : There are no images anymore--such as the logo of sender company the top the page.

Do you mean you select an email to read and in the Message Header area where it says 'From' the sender logo is not displaying? If yes: Click on 'More' and select 'Customise' Select : Show senders profile picture' Click on 'Done'

OR are you talking about the content of the email itself ? Sounds like you might be viewing 'Simple HTML' so... Please check to see if you have this setting. View > Message Body as > Original HTML

Do you normally allow remote content to display ? It's not advisable, but check this and report on what is selected. Settings > Privacy & SEcurity Is this selected or not.....'Allow remote content in messages' ? By default, Thunderbird will not select that option as remote content means it's not part of the email and needs to access the internet to download and display content.