How to resolve Apple Mail issue where message list doesn't match full message?

Question

I am running Big Sur 11.2.3 (20D91) and Apple Mail. Today, a good number of my messages in Apple Mail no longer match the full message when I click on the message list.

For example, the message list may show a message from Apple Store, but when I click on it, the full message that shows on the right is a completely different message and sender.

I have deleted the IMAP folder under ~/Library/Mail/V8/{IMAP folder guid} but after the mail downloaded it still had the problem.

Not sure what else to do.

Answer 1

I was able to solve the problem by deleting (make a backup first, just in case) the Envelope files under the MailData folder:

~/Library/Mail/V8/MailData/{Envelope}*

This will result in Mail reimporting all your mail messages, but after that, the message list and full messages were correct for me.