Henri, This is a problem even if you do use Exchange distribution groups, which I believe is your only recourse. Microsoft recommends that when, in Outlook, you are inviting a group of people using a distribution group, you should click the "plus sign" to expand the group into individual accounts. That way, if you do alter the meeting, all of the individuals get the updates. You can read their recommendation, and many others for using Outlook for calendaring, at http://office.microsoft.com/en-us/assistance/HA011276781033.aspx. We have the same problem here. We just live with it, or invite users individually. We need Listserv because we need to send messages to large groups of users who do not have an HMS e-mail account, and don't want the hassle of creating distribution groups. Melissa Kenny IIS Administrator Harvard Medical School IT 107 Avenue Louis Pasteur Center for Educational Technology Boston, MA 02115 -----Original Message----- From: LISTSERV list owners' forum [mailto:[log in to unmask]] On Behalf Of Bulterman, Henri R. Sent: Monday, June 19, 2006 6:24 PM To: [log in to unmask] Subject: List Server and Outlook Calendar Invitations Hi, All -- These days MITRE uses Exchange for mail and calendars. Our list server includes lists for all the organizational entities (departments, divisions, etc) at MITRE. We know that there is a problem with the Outlook calendar and the lists on the list server: Users can apparently send an invitation to a list on the list server, and that works OK, but if they then update the meeting things get a bit messed up, with duplicate meetings scheduled. My question to you: Is this a fixable problem, and (if so) has anyone figured out a good way to deal with it? It seems that our only recourse at this point is to create Exchange distribution lists for every organization at MITRE, but if there is any workaround we'd sure like to try it. Moreover, if anyone can provide some technical details of the underlying issues I'd appreciate -- feel free to mail me directly. Thanks, Henri Bulterman Principal Software Engineer The MITRE Corporation [log in to unmask] =20