I created a new message in Mail with some pictures attached. When I noticed it was more than 10 MB, I didn't send it and deleted the draft. But my settings included "synchronize drafts with server", which I turned off now. Mail.app apparently tries to load the message again and again, and it appears in a local folder (recovered mails) even after I deleted it several times. Meanwhile there are four duplicates of the message with about 45 MB worth of attachments in this local folder.
The worst thing about it: Mail does not get new incoming emails.
What can I do about it?
OS X 10.7.3 and Mail Version 5.2