This is a fairly common problem for users who send meeting requests to Internet addresses.
When we forward appointments to another employee, the employee receives a vcalendar attachment that opens as a Calendar entry on their copy of Outlook. When we send it to someone using POP3 email, the attachment is simply a forwarded email message, with the vcalendar text as the email body. When the POP3 users forwards appointments to us, calendar entry, it arrives as a proper appointment. Is this an Outlook configuration issue, or an issue of Exchange vs POP3 message processing?
It's a little of both, but we'll start by blaming Outlook because you can usually prevent problems by changing Outlook's configuration. When you forward an appointment in Outlook's native format, the message is in RTF format. Outlook's default is to convert RTF to HTML when sending to an Internet address plus the Exchange server can be configured to never send RTF to the Internet (it converts them to HTML). Either of those settings can make meetings and forwarded appointments (and other Outlook items) not work as expected when sent to an Internet address.
The easiest fixes are on the user side:
When forwarding an appointment outside of the Exchange server, you should choose the option to forward as an iCalendar.
For meeting invitations, check the setting in File, Options, Calendar – 'When sending over the Internet, use iCalendar format' should be checked. (That option is in File, Options, Calendar in Outlook 2010.)
Published January 24, 2012. Last updated on August 15, 2012.