KCC Replication Path Computation

Applies To: Windows Server 2008

The Knowledge Consistency Checker (KCC) is a component of Active Directory Domain Services (AD DS) that is responsible for generating the replication topology between domain controllers. Generating an efficient and fault-tolerant replication topology is an integral part of achieving data consistency between domain controllers.


Event ID Source Message



The Knowledge Consistency Checker (KCC) has detected problems with the following directory partition.

Directory partition:

There is insufficient site connectivity information for the KCC to create a spanning tree replication topology. Or, one or more directory servers with this directory partition are unable to replicate the directory partition information. This is probably due to inaccessible directory servers.

User Action
Perform one of the following actions:
- Publish sufficient site connectivity information so that the KCC can determine a route by which this directory partition can reach this site. This is the preferred option.
- Add a Connection object to a directory service that contains the directory partition in this site from a directory service that contains the same directory partition in another site.

If neither of the tasks correct this condition, see previous events logged by the KCC that identify the inaccessible directory servers.



A call to the Intersite Messaging service that specifies the following transport failed.


As a result, the Knowledge Consistency Checker (KCC) cannot configure a correct intersite replication topology.

User Action
Verify that the Intersite Messaging service is running.

Additional Data
Error value:
%3 %2



The Intersite Messaging service could not read the intersite transport objects from AD_TERM.

As a result, the Intersite Messaging service has stopped. The Knowledge Consistency Checker (KCC) will be unable to calculate intersite topology without this service.

User Action
Verify that LDAP queries function properly on this machine.

Restart the Intersite Messaging service to continue intersite communication.

Additional Data
Error value:
%2 %1 .



The Connection object translation task in the Knowledge Consistency Checker (KCC) is disabled. This configuration is for internal testing purposes only.

User Action
To enable the translation task, use the Repadmin command-line tool and run the following command-line task.

repadmin /options "server" -disable_ntdsconn_xlate



The Knowledge Consistency Checker (KCC) was unable to form a complete spanning tree network topology. As a result, the following list of sites cannot be reached from the local site.


Partition Replication

Active Directory