TRy repairing the folder.

• Right click on folder and select 'Properties'
• click on 'Repair Folder'
• click on 'OK'

As you experienced a similar issue before - Did you create a backup of profile name folder prior to updating?

Going back to a previous version may not suddently display correctly and it is not quite so straight forward as uninstalling and reinstalling, but it is possible.

Do you compact folders on a regular basis? Do you allow Anti-Virus products to scan Thunderbird files and folders?

Repairing the folder as you suggested worked perfectly. Thank you. The errors occurred possibly just as the update came in. They were all on January 11, 2022 messages.

I have the same problem. However repairing folders is only a temporary fix. As soon as I navigate away and back, the recently (since upgrade?) received emails are hidden, once again.

I can see the emails in question with a global search of the folder.

Oh, the horror. Thunderbird should have provided an easy way to get back to the previous version of thunderbird. I regret having the automatic updates on. I have similar problems and opened a ticket at https://support.mozilla.org/ro/questions/1365903. Repairing the inbox folder didn't help.