To open a piece of mail, I have to exit and go back in every time
To open a piece of mail, I have to exit Mail and go back in every time?
iMac 21.5″ 4K, macOS 12.6
Safe Boot from the HD, (holding Shift key down at startup), does the problem occur in Safe Mode?
Safe mode attempts to repair Disks & clears lots of caches, so if Safe Mode works try again in regular boot.
If you have no POP accounts & they’re all IMAP accounts then in Mail’s Mailbox menu choose Rebuild.