click the little square bit on the line that would normally have headings on it and select "restore column order. That should fix things I think.

Could you please send me a high resolution PNG file of the image you uploaded. I have never actually seen this, so would like to write some documentation for it but the image is very low resolution as it appears here. EMail the image to matt_au at gmx.com.

Hi Matt - Thanks so much for offering assistance. I really appreciate you taking the time to explore this. Unfortunately, I tried your fix, but it didn't work. I followed through and sent a couple of images to you. Hope it helps your solving of the mystery! I am going to uninstall and reinstall TBird to see if that helps out. I will post results.

Best, Chris

If resetting the headings did not work, the next logical cause is an add-on. I vaguely think I recall hearing the conversations addon did this to some, but restart Thunderbird from the help menu with addons disable to see if one might be the cause. Continue into safe mode when prompted

OK, I tried it, but it didn't work. Crazy, huh?

BTW, I uninstalled and reinstalled last night and it didn't help either.

Thanks for your help with this . . .

When you select such an 'invisible' message, and move it to another folder folder, will the message subject become visible again in the thread pane?

There are more than 2000 unread messages in your Inbox, and probably many more read ones. So my best guess is your mail file(s) got corrupted. Anti-virus software may have contributed to that.

In any case, accumulating messages in Inbox is always a bad idea. Keeping your Inbox as tidy as possible is best practice.

Thanks for the tips. I deleted a lot of old emails.

When I move messages to other folders, they do not appear.

E-mails in all other folders are all visible.

You still do not appear to have any column headings. when the menu is open, try selecting Subject,Date and correspondents from the menu and see if something you can read appears.

I am thinking there is a bug that has removed the restore default from the menu. Reset heading appears to only reset the order of what is visible here.

Thanks very much. I hadn't known about the little box with options for viewing "Conversations," etc. in the in-box. For some unknown reason, all those options had become unchecked in my main email account but not in a secondary one. Problem is fixed now.