I have several similarly configured systems with XP SP2 and Outlook 2003
accessing mailboxes on an Exchange 2003 server. On most of them, Send To>
Mail Recipient works as expected. On a few, it doesn't do anything. If I
right click a file in Explorer and choose Send To> Mail Recipient on one of
the problem machines, nothing happens. No error messages, nothing in the
event log. If I use the send email function in Word, I get an alert that
says:
Word couldn't send mail because of MAPI failure: "Unspecified error".

I've examined the usual suspects. Outlook is the default MAPI client, and
I've unregistered/re-registered sendmail.dll. If I change the default mail
app to OE, it will compose an OE message, but when I change back to Outlook,
I get nothing.

Any ideas?