I currently have an Exchange 2003 Mailbox server, Exchange 2007 CAS, 2010 CAS and 2010 Mailbox server. The 2003 and 2007 are being phased out to be replaced by 2010. I have an all 2008 R2 Active Directory Domain. No other domain or forrests. I granted a person the right to manage a Dist. Group but everytime she goes in to add/remove members she gets "Changes to the public group membership cannot be saved. You do not have sufficient permission to perform this operation on this object." However, she does. I am a domain admin and I get the same error, but if I open up Active Directory Users and Computers I can do everything fine.