We're running System Center Configuration Manager 2007 on a Windows Server 2008 R2 Standard server. It polls Active Directory for our workstations. For some reason, it finds all but four of our workstations. All these workstations (both the ones that are discovered and those that are mysteriously skipped) exist in the same OU in AD. All machines are of the same configuration (identical hardware, OS, software installations, etc). Can anyone here please provide a suggestion as to why SCCM 2007 might not add these four machines to it's collections while all the other machines are added?