"Domain Users" group is empty when I use DirectoryServices "member" property

Unless you change the primary group id of a user, the user is not stored in the member attribute of the Domain Users group, rather it uses the fact that the primary group id is set to the Domain Users RID to determine membership in Domain Users. The normal case is that the Domain Users member attribute is empty; it would require that you make some changes to the default Active Directory implementation for this to not be the case.

The Domain Users group uses a "computed" mechanism based on the "primary group ID" of the user to determine membership and does not typically store members as multi-valued linked attributes. If the primary group of the user is changed, their membership in the Domain Users group is written to the linked attribute for the group and is no longer calculated. This was true for Windows 2000 and has not changed for Windows Server 2003.

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