In one of my mailboxes, I can no longer remove e-mails. Every time I want to delete a mail, it gives me the following message:
"247263.emlx" couldn't be copied to "Messages" because an item with the same name already exists.
I have already tried to rebuild the mailbox, but without any result.
How can I fix this issue?
(MacBook Pro Retina, Mid 2012, OS X 10.11.4)