If you have ever run dcDiag and ended up with the error output as follows:
Starting test: VerifyEnterpriseReferences
The following problems were found while verifying various important DN
references. Note, that these problems can be reported because of
latency in replication. So follow up to resolve the following
problems, only if the same problem is reported on all DCs for a given
domain or if the problem persists after replication has had
reasonable time to replicate changes.
[1] Problem: Missing Expected Value
Base Object:
CN=OLDDC,CN=Domain System Volume (SYSVOL share),CN=File Replication Service,CN=System,DC=domainName,DC=loc
Base Object Description: "SYSVOL FRS Member Object"
Value Object Attribute Name: frsComputerReference
Value Object Description: "DC Account Object"
Recommended Action: Check if this server is deleted, and if so
clean up this DCs SYSVOL FRS Member Object. Also see Knowledge
Base Article: Q312862
[2] Problem: Missing Expected Value
Base Object:
CN=OLDDC,CN=Domain System Volume (SYSVOL share),CN=File Replication Service,CN=System,DC=domainName,DC=loc
Base Object Description: "SYSVOL FRS Member Object"
Value Object Attribute Name: serverReference
Value Object Description: "DSA Object"
Recommended Action: Check if this server is deleted, and if so
clean up this DCs SYSVOL FRS Member Object. Also see Knowledge
Base Article Q312862
……………………. DC01 failed test VerifyEnterpriseReferences
This probably occured from a lost DC that was never fully cleaned up or some similar hoursekeeping task that doesn't cause any type of error generation on day to day tasks.
To clean this up you will want to bring up ADSIEdit and browse to the object and right click on it and delete it. Obviously you will always want to get a backup in the event of some unknown issue.
Details from Microsoft that discuss this http://support.microsoft.com/kb/555846