I have a weird issue that only seems to be happening with Outlook 2010 users: they double click on a meeting cancellation message in their inbox, and get the following message "the meeting cannot be removed because you are the meeting organizer. When you are a member of a contact group that is removed from the meeting attendee list, a cancellation message might appear" which then disallows them to remove the meeting from their calendar. The issue is they are not the meeting organizer and the message is saying they are. Also they are able to remove it manually from the calendar. Backend server is Exchange 2003, with Outlook 2010 on the front.