Open up Outlook and in the File menu, click, "Work offline", then close Outlook down.
Reboot the computer into Safe Mode, open up Outlook again, and see if you can delete the message now.
If so, reboot the computer for a normal start-up, open up Outlook again and remove the "work offline" option.
Hope it works
Mark
I replied to an email message and my reply has been stuck in Outlook's "Outbox" for 3 days. I tried to open the reply up to delete it, but a dialogue box pops up and says: "Can't open this item. Outlook has already begun transmitting this message."
Othewise Outlook works fine, and it continues to receive and send all my other messages. Please help.

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