No Cluster Witness Has Been Configured

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2008-03-19

The Microsoft Exchange Analyzer Tool examines the following registry entry to determine the version of the Microsoft Windows operating system that is running on the computer:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\CurrentVersion

Version values are as follows:

CurrentVersion value Microsoft Windows operating system


Microsoft Windows NT® Server 4.0


Microsoft Windows 2000 Server


Microsoft Windows Server™ 2003


Microsoft Windows Server 2008

The Exchange Server Analyzer then counts the instances of the following registry key to determine the number of nodes in the cluster:

HKEY_LOCAL_MACHINE\Cluster\Nodes\<Node Number>\NodeName

The count of the instances of the NodeName registry key represents the number of nodes in the cluster.

The Exchange Server Analyzer then queries the QuorumType property of the MSCluster_Cluster Microsoft Windows® Management Instrumentation (WMI) class to determine whether the quorum type set is Node Majority.

The Node Majority quorum type can sustain failures of half the nodes minus 1.

Finally, the Exchange Server Analyzer queries the PartComponent property of the MSCluster_ClusterToQuorumResource (WMI) class to determine whether a quorum resource has been defined.

The quorum resource allows the cluster to maintain its state and configuration independently of individual node failures. The quorum resource stores a constantly-updated version of the cluster database and is accessible to all cluster nodes.

Failover clusters with an even number of nodes usually use a quorum resource configuration that includes a "witness disk" or "witness file share." In a cluster with an even number of nodes and a quorum configuration that includes a witness, when the witness remains online, the cluster can sustain failures of half the nodes.

If the Exchange Server Analyzer determines that all of the following conditions exist, the Exchange Server Analyzer displays an error.

  • The computer is running on the Windows Server 2008 operating system as a node in a cluster.

  • There are two nodes configured in the cluster network.

  • The quorum type is set to Node Majority.

  • There is no Cluster Witness configured as the quorum resource.

A Windows Server 2008 Node Majority Quorum with only two nodes in the cluster network is not a valid configuration. This configuration requires that a Cluster Witness be configured as the quorum resource.

To address this error, it is recommended that a File Share Witness be configured as the Cluster Witness quorum resource. You should setup and secure a file share on a separate computer, and configure the cluster to use a Node and File Share Majority quorum.

To setup a file share as the quorum resource

  1. Follow the guidance of the Exchange 2007 topic How to Configure the Node and File Share Majority Quorum (

For more information about Exchange 2007 Cluster Continuous Replication (CCR) on Windows Server 2008, see Installing Cluster Continuous Replication on Windows Server 2008 (