I did the same thing once. I called my ISP and the tech walked me through deleting the outbox. Once I re-booted, the outbox restored, but without the large file. Sorry, but I do not remmeber what we did. Microsoft might have a fix in their troubleshooting or knowledge base. Last ditch effort would be to delete Outlook but you would need to abck up your contacts and any other improtant .pst folders first.
I attempted to send a large file to 2 people. Apparenly, the file is too large and Outlook keeps trying unsuccessfully to send it. I can't get into the file to change it and I am unable to delete it. I just get the message that Outlook has started to send the email so I cannot access it. Any suggestions for a fix here would be appreciated.

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