Large file in outbox

[Peter]

I inadvertently tried to attach and send a very large file. It is now stuck
in my outbox. How do I get rid of it?

 

[Gordon]

I inadvertently tried to attach and send a very large file. It is now stuck
in my outbox. How do I get rid of it?

As posted in all the Outlook groups on a pretty frequent basis:

Click File and check Work Offline. Close and then restart Outlook. Delete
the message. Click File and uncheck Work Offline.

If that doesn't work, try this:
http://www.outlook-tips.net/howto/stuck_message.htm