Configuration Manager - Extend the Active Directory Schema

Extending the Active Directory schema is a forest-wide action and can only be done one time per forest. 

Important considerations for Active Directory schema extension:

1. All Configuration Manager site systems must be members of an Active Directory domain.
2. The schema does not need to be extended again for Configuration Manager 2012, if it has already been extended for Configuration Manager 2007.
3. Update the Active Directory schema before or after you install Configuration Manager.
4. Schema updates do not interfere with an existing Configuration Manager 2007 site or clients.
5. Schema changes are stored in \SMSSETUP\BIN\x64\ConfigMgr_ad_schema.ldf