'Concept' or 'Drafts' folder counts send messages, but folder empty (IMAP)

Question

In mail my 'concept' (dutch) or 'drafts' folder counter says there are messages in the folder, but the folder is empty.
Everytime i send a message with mail, my concepts folder counts up. When going to my Webmail en delte the "drafts" folder, The whole folder is gone. But when sending a new message the folder appears again, and counting up for every new message witch is send.
The folder is always empty, and the 'counter' disappears when looking in the folder but can appear again every moment.
Synchronising the account doesn't help.
Iam working on a Intel Imac, using a Imap server with 2 different accounts.

Answer 1

You're welcome.
There seems to be nothing amiss in your account folder, and from the description of what you did, it looks like trying to synchronize mail on both computers is indeed the cause of your problems. Synchronization of local mail data between computers by means of a file synchronization utility is a really bad idea if more than one computer is allowed to access mail between synchronizations.
The most prominent issue is that Mail keeps a reference to every message within the ~/Library/Mail/ folder in a global Envelope Index file. If this file is modified in more than one computer between synchronizations, there is no way a file synchronization utility can handle the situation properly.
Another, more subtle, and potentially more dangerous issue, is that Mail may use different *.emlx sequence numbers to name the same message in different computers or, worse yet, the same sequence number to name different messages in different computers. Again, the only thing a file synchronization utility can do about it is either overwrite files with the same name (thus potentially losing data) or not synchronize them at all.
Mail data "synchronization" at the filesystem level can only be done reliably if it's a one-way operation, i.e. if the entire contents of the Mail folder in one of the computers are overwritten by the entire contents of the other, and even then it may not work properly because of the issues described here:
Mac Backup Software Harmful
You're going to have to re-create both the index and the entire contents of the .Mac account folder on both computers:
1. Quit Mail.
2. In the Finder, go to ~/Library/Mail/. Make a backup copy of this folder, just in case something goes wrong -- e.g. by dragging it to the Desktop while holding the Option (Alt) key down.
3. Locate the Envelope Index file and move it to the Trash. If you see an Envelope Index-journal file there, delete it as well.
4. Move any "Mac-" or "IMAP-" account folder (Mac-neilwedlake in your case) to the Trash. Note that you can do this with IMAP-type accounts because they store mail on the server and Mail can easily re-create them. Doing the same with "POP-" account folders would cause all mail stored there to be lost.
5. Open Mail and proceed to re-create the index -- Mail says it's "importing", but it just re-creates Envelope Index if the mailboxes are already in Mail 2.x format.
Note: For those not familiarized with the ~/ notation, it refers to the user's home folder.