Originally Posted by
Gary86 when I delete the email off one device it removes from all other.
I have not found this to be entirely true. While deleting an email from a iOS device removes it from OS X Mail.app, the opposite is not true. If you delete a email from within OS X Mail.app, it won't instantly delete from iOS devices - it'll in fact not update the mailbox state until you either open the iOS Mail app, or a fetch or push occurs. So you could have your iPhone reporting two unread, but Mail.app reporting zero unread.