I am on an Exchange 5.5 server running MsOutlook workgroup. When I send a calendar appointment to someone on internet Outlook email they receive it as a text email rather than a MSOutlook appointment. I have been told by Microsoft Support that this is a known bug in an Exchange 5.5 environment. However, I find that hard to believe. Any suggestions or ideas? I've sent these appointments as RTF and MIME and get same results.