This maybe an Outlook issue, but wanted to ask the Exchange experts. We are on Exchange 2003, Outlook 2003. Calendar events from some outside Organizations (also on Exchange/Outlook 2k3) come through as .msg attachments, and the "Accept", "Tentative", and "Decline" options are grayed-out, so they can not be automatically added to one's calendar. One of the "problem" organizations sent a copy of how their Internet Message Format is set for MIME encoding, and it was "Both" HTML and Plain text. They did not let me know how "Exhcnage rich-text format" was set. I tried to duplicate this problem between my Exchange test environment on my VM machines, which I am able to communicate with my production Exchange because of the SMTP connectors I have set up. I can not duplicate the problem, changing all the Exchnage settings just mentioned, and also changing the Outlook Option settings for Mail format, HTTP, Rich text, etc. and Interent Format. I do not have access to the mail-relay and spam servers that all our SMTP mail comes through, which resideoutside our firewall, and it would seem that if that were something they did, all incoming Calendar events from any outside organization would not work, but some do. Does anyone know if some sort of Exchagne setting, firewall, spam filter, etc.could change the Calendar event e-mail in some way that could cause this, or is it the senders Outlook settings? BTW, with the couple of "problem" organizations, they do not have a problem when I send test calendar events to them. Our Exchagne Iternet Message Formats and my Outlook settings are default. thanks