Exchange 2010 Resource Mailboxes and Groups-based Delegation

Ran into an annoying issue the other day and it turned out to be a “bug” in the product.

So a large enterprise customer is currently migrating to Exchange 2010. When it comes to resource mailboxes (room and equipment), they add groups as delegates of a resource mailboxe as shown below:

In addition, security policies state that all meeting requests send to a resource mailbox must be approved by a member of the group that is set as a delegate of a mailbox.

After having configured this, the members of a delegated group received the following error message when trying to approve a meeting request:

After further examination, it turned out that the group was added as delegate on the “Calendar” folder, but permissions was set to “None”:

As some of you probably know, when you add a user as a delegate of a resource mailbox, the calendar permission is set to “Editor” as shown below:

To fix the issue, you can change the permission to “Editor” via Outlook or use the “Set-MailboxFolderPermission“ cmdlet:

Set-MailboxFolderPermission -Identity “resourcemailbox:\Calendar” -User “Group” -AccessRights Editor

If you want to add delegates to a resource mailbox using PowerShell, you can use this command:

Set-CalendarProcessing -ResourceDelegates “Group” -Identity “Resourcemailbox”

Until later,

Henrik Walther
Technology Architect/Writer/MS Vendor
MCM: Exchange Server | MVP: Exchange Architecture