We have an issue with a couple of users creating meetings in Outlook 2007. When the meeting is created and sent out for acceptance the list of attendees will show duplicates after acceptance. This happens only after acceptance. However, if an update is made to the same meeting and sent back out for acceptance a second time, then the duplication is removed. This seems to be user specific as I have setup the same user's Outlook profile on another machine and experience the same problem.