I have a mail account with lot of e-mails stored on server (around 100 thousand). I would like to clean it using Mail app and delete all unnecessary messages. But so far no luck Store deleted e-mails on server is UNCHECKED. Move deleted messages to Trash is UNCHECKED. When I delete the messages they seem to disappear, but they appear again when I click on a different mailbox and back to the current one or when I restart the Mail app. I have tried deleting all content of ~/Library/Mail/V2 folder and reimport all e-mails but it didn't help. I have also tried to check the Move deleted messages to Trash, but then I am getting following error when exiting the Mail app: Also the Mail app seems to freeze when I try to exit. Or is it trying to delete the e-mails? I have tried to leave it open some hours but it didn't help neither. Any suggestions? P.S.: The account is connected using IMAP.