Try this Microsoft fix:
http://support.microsoft.com/default.aspx/kb/941090
"Messages may be stuck in the Outbox when you use Windows Mail on a
computer that is running Windows Vista"
That page offers two download options. Unless you know for sure
you have 64-bit Vista, use the 32-bit option.
Although only 'Outbox' is mentioned, it will enable removal of stuck
emails from any folder.
--
Gary VanderMolen [MS-MVP WLM]
"tom" <tom@discussions.microsoft.com> wrote in message news:AAFE786E-F908-41B4-8C62-3FD9E7330B2E@microsoft.com...
>I cannot delete an email. I receive a message alert stating that an unknown
> error has occured.
> --
> Tom