Q: My mail all of a sudden would not allow me to delete messages in my inbox saying, "couldn’t be copied to “Messages” because an item with the same name already exists." Found it duplicates the message I wanted deleted in trash.

Still  using the @mac.com   mail  address and up   to date on everything, but have not gone to Maverick.  All of a sudden Mail wouldn't let me delete.  Said that title of email was already in trash.  And sure enough it was.  Clicking on the help button on the message gets Nothing.

The selected topic is currently unavailable.

The topic you were trying to view could not be found.

"couldn’t be copied to “Messages” because an item with the same name already exists."

Any ideas.  My mail is not tied to gmail etc.. just all by it's lonesome.