We are having an issue with Room Mailbox resources in Exchange 2007 and Outlook 2010. We have several Room's in our company and they all work fine, with the permissions as follow: Name Permission Level Default Author Anonymous None I am a part of a "Security Group" that has full access to this Shared Mailbox, so I can view, edit, and change all of the information just fine. Here are the following permissions for the shared mailbox under the Exchange Management Console: Send As Permission: NT AUTHORITY\SELF Full Access Permission: <Our domain>\Exchange Domain Servers <Our domain>\<My security group> NT AUTHORITY\SELF Regular users can view the calendars; however, when they try to Add an appointment to that Room Mailbox it does nothing and a message pops up saying: "Cannot open the free/busy information" and the other Calendar says: "Cannot open this item. Cannot open the free/busy information". The calendars are identical to the other calendars, except for this free/busy information. I cannot find the free/busy permissions in Exchange 2007 for these newly created Room Mailboxes, or even in Outlook 2010. I have already tried: outlook.exe /cleanfreebusy Can anyone explain what is going on? Or does anyone have an idea how to fix this? Thanks, -R-

Update: I have also exported all of the SchemaDefault and Inherited permissions of both Room Mailbox (users) to a text file, and after comparing their Active Directory permissions, they are identical. Is there possibly some other place that could be different? Active Directory permissions are the same, Calendar Properties Permissions are the same, Exchange: Send As Permissions and Full Permissions are the same. Yet the new Room Mailbox Calendar still comes up with: "Cannot open the free/busy information", unless I explicitly add each individual user to the Calendar Properties Permissions.