I'm working on a third party service that creates events and invites a group of participants / rooms to attend those events. I do this by creating .ics files (iCalendar file format) and mailing them (from an outside account) to the participants. This works great for regular attendees. Exchange automatically parses the .ics file and shows the attendee a nicely rendered invite that integrates with the recipient's calendar.

The problem is, I have not been able to use this technique to schedule a room. If I send an invitation to the room's address, the room does not book itself. I've tried everything I can think of. The room is configured to auto-accept invites, and I've looked for permission settings that might influence this feature. I'm starting to think that the behavior I want (scheduling a room in Exchange through an externally generated ics file) is not supported. Has anyone else tried this and been successful? Does anyone know for sure whether this is supported?

FYI I'm testing with Office 365.

Have you set the ProcessExternalMeetingMessages to True using Set-CalendarProcessing ? eg see https://technet.microsoft.com/en-us/library/dd335046%28v=exchg.150%29.aspx

Cheers
Glen