I am running Exchange 2003 in a windows 2000 AD and I am having problems with owners of mailing list not being able to add/remove users. The checkbox for "Manager can update membership list" is checked. The user has "write member" permission on the DL. What is a little odd is that I think it is a problem with the Exchange server and not AD. Users on other Exchange server, in the same domain, have no problems. I have assigned ownership of my test DL to users in different OUs and the single factor that seem to determine whether or not the user can make changes to the DL is the server in which the mailbox of the user reside. Any suggestions would be appreciated.