Completely delete Exchange account from Mail client on Mac

Question

I'm having a problem with a several e-mail messages in my Mail client.  These messages seem "stuck" in that whenever I try to delete these messages, I get an error message in Mail that says:
An error occurred while moving messages to mailbox “Trash — Exchange”.
I named the account Exchange.  These messages are NOT on my Exchange mail server anymore - I also access my mail from an Outlook client as well and these "stuck" messages do not appear in Outlook which is pulling directly from Exchange.
My first attempt to resolve was to delete the account from the Mail client and set it up again.  All of the folders and e-mail messages re-appeared almost instantly so it obviously didn't go out to the Exchange server and pull down over 100K e-mail messages in 30 seconds.
Then I spoke to AppleCare.  They directed me to the Library to delete a subfolder in the Mail folder that appeared to contain the messages.  When I emptied the Trash, it appeared that the 100K messages were being deleted.  I went to Mail to setup the account again.  Again, the messages reappeared quickly as before and the problem messages were still there as if they never were deleted.
So now I'm looking for a way to completely the Exchange account and all of its local data from Mail.  I want the Mail client to start from scratch and go out to the Exchange server to get the data like the account had never been setup on this Mac before.  I'd also opt for a fresh install of Mail but I have a MBA 11 so I don't have OS media or a DVD drive.
Somewhere Mail is clealry caching info on that account.  It's apparent when I've deleted the account and then re-opened Mail to set it back up the first time.  Whenever the dialog box appears, it remembers my Exchange e-mail account information in the field so it's obviously pulling that information from somewhere locally on the Mac, not from the server.

Answer 1

As you say, removing the Exchange account on Mail really doesn't delete it. It's caching something because of how quickly it finds the folders etc. if you add the account again.
I was having a lot of very strange problems with Mail/Contacts/Calendar and certainly a new user I set up from scratch worked with Mail etc. straight away. I didn't test it for days but within seconds it pulled down all the correct emails and the number of unread tallied with my iPhone which was one of the annoying problems I was having.
One of the things I read elsewhere is how useful doing a Mailbox/Rebuild from within Mail is. I just tried it now on my existing user name and it certainly seems to have helped. It immediately refreshed the Inbox and had it accurate. However, despite having it set to "1 min checking for new mail" after several mins it seems to have hung again and isn't refreshing.
Mail for OSX has caused me a million more problems that for iOS which just works every time. I don't see how Apple can make it work so smoothly on iOS and give loads of problems on OSX.
Have you tried the Mailbox/Rebuild?