Additionally, you may receive an error message that resembles one of the following when you try to change the distribution list membership in Outlook:
The Delegates settings were not saved correctly. Unable to activate send-on-behalf-of list. You do not have sufficient permission to perform this operation on this object.
For more information about the hotfix that is included in Update Rollup 6 for Exchange Server 2007 Service Pack 3 (SP3), click the following article number to view the article in the Microsoft Knowledge Base:
Article ID: 2732525 - Last Review: 4 Sep 2013 - Revision: 1