I'm on a MAC. Thunderbird is 128.2.0ers. No firewall nor VPN. When the email comes in the MAX shows it in the top right corner.

It was gotten bad that I have to read my iPhone and iPad to read my emails.

Is this the issue: ignore thread flag. WHERE IS IT?

Perhaps you might try the knowledge base for information on Threading. https://support.mozilla.org/en-US/kb/message-threading-thunderbird#

The following didn't do anything:

Type mailnews.default_view_flags into the Search preference name search box.

Not sure about threading. The incoming emails ate not related.

I have seen that when the notification arrives on the top right of the display, and I click on it, I can read it it and then it is my in box.

After a wile they show up; maybe 10-20 min., and it helps to check on the total address and then on the inbox.

You do realize that Thunderbird only checks mail based on a time thing around every 15 minutes based on your settings in the account settings. But I would expect the messages to appear as soon as you are notified of them.

I have heard of a few update glitches where you need to change folders to another in the folder pane and back again to force a list refresh however. Could that be it?

Thank you Matt as the only help I received. I have used -- and supported -- both Firefox and Thunderbird for decades. I continue to have problems with Thunderbird. Now the current messages are showing up as they should. But now they stay bold and never without bold. (Thus the number that shows up on the bottom taskbar is not indicative of unread messages. Now everything is bold!) Years ago I never had these problems. Maybe it's the MAC. Whatever the cause I feel that I would be better off with a email client that has paid support. Emails have gotten so important that missing some is not an option. I find that I look directly at the Google app to very that I am not losing any.

I thank you for your help and your comments would be appreciated.