We are running Exchange 2010 SP2 (the issue also occurred on SP1) on Windows Server 2008 R2 SP1. This is a Server 2003 AD domain and many clients are running Outlook 2010 with the exception of a few who are using Outlook 2007. The problem which we have been having for a while now is that when a user creates a meeting and uses a room (in this example I have setup a room called "Guest Parking") they are not being sent a declined request when there is a conflicting meeting and are also not being sent a confirmation when the meeting is accepted. This does not happen for all users. Some of my test results are below: I send a meeting request to someone in my department for a specific date from 10:30am to 11am. They accept the request and the meeting is scheduled on the rooms calendar. I have a co-worker in my department send me a request for the same date and time. I received the meeting request, and she receives a declined message from "Guest Parking" because of the time conflict. The meeting does not show up on the rooms calendar. Because this works correctly, I tell a user in another department to send me a meeting request for the same date and time. When she sends one, I accept the request, but the room does not send her a declined message for the time/date conflict. The meeting does not show up on the room calendar. This same result occurs when I have someone in the sales department try it as well. One thing that I did in an attempt to fix this was as follows: Enabled Guest Parking user account, opened Outlook on a spare machine, went into Tools > Options > Calendar Options > Resource Scheduling > Enabled Automatically accept meeting requests and process cancellations. Also enabled Automatically decline conflicting meeting requests. This did not resolve the issues. Changed back to original settings. The "Allow conflicting meeting requests" is NOT checked when I got into the room properties, and appears to work for some users as they DO receive the declined notices. Anyone that is a domain user should be able to use this room for a meeting as well as any other rooms we have setup. If I can provide any more information to be helpful, please let me know. If anyone has suggestions on where to look or how I can resolve this, it would be very much appreciated! I have spent a bunch of time on this issue and I'm out of ideas at this point.