We have a few users in our company experiencing an issue where certain
meeting requests will drop off their calendar before the recipient has
a chance to accept or decline the request.  Initially when the request
is delivered to the recipient's inbox, the calendar shows the time as
tenative.  After a random amount of time (usually less than a couple of
hours), the tentative "meeting" drops off the recipient's calendar.  If
the recipient accepts the request, the meeting appears on the
recipient's calendar as expected and remains there.  The user is
running Outlook 2003 SP1.

Any assistance would be appreciated.

Thanks, Kevin