See if the info here helps:
http://www.howto-outlook.com/faq/mes...ckinoutbox.htm

"Ronsports" wrote in message
...
I tried to send a large video file with my Outlook 2007 from using Windows
Vista.

Now, I can't get Outlook to send that message and since that time Outlook
has not been working properly. I cannot delete the large message/file that
I
tried to send.

Cannot delete the large file.