For future reference…

I was having an issue in which emails in a thread were not displaying the correct contents. This was happening primarily with my gmail IMAP account from the Standards Ebook mailing list which made it particularly frustrating.

I tried deleting and or rebuilding the mailboxes and even deleted the whole gmail mailbox (~/Library/Mail/v7/AFD4138D-113E-4798-BA9B-A928C0A9EC44/) all to no avail.

Finally I came across this Mail shows wrong message body (finding the right term to Google makes it so much easier…)

The Solution:

• Quit mail.
• Go to ~/Library/Mail/v7/MailData/
• Delete
  Envelope Index
  ExternalUpdates.storedata
  and any variants
• Restart Mail and let it rebuild (this will take some time).

So far this seems to be working…