Knowledge

ERROR_CLUSTER_NO_QUORUM - 5925 (0x1725)

A quorum of cluster nodes was not present to form a cluster.

Updated: Feb 21, 2026

Technical Background

The ERROR_CLUSTER_NO_QUORUM error indicates that the required quorum of nodes in a Windows Failover Cluster is not present, preventing the cluster from forming or operating correctly. This error typically occurs during the initial formation of a cluster or when there are node failures.

Error Details

  • Error Name: ERROR_CLUSTER_NO_QUORUM
  • Numeric Code: 5925 (0x1725)
  • Short Description: A quorum of cluster nodes was not present to form a cluster.

This error is specific to the Windows Failover Clustering environment and indicates that the system cannot achieve the necessary quorum for operation. The quorum requirement ensures that there are enough nodes available to make decisions in the event of node failures, thus maintaining the availability and reliability of the cluster services.

Common Causes

  • Node Failure: One or more required nodes have failed or are not responding.
  • Network Issues: Network connectivity issues preventing communication between nodes.
  • Configuration Errors: Incorrect configuration settings for quorum requirements.
  • Resource Limitations: Insufficient resources to meet the quorum requirement.

Real-World Context

In a Windows Failover Cluster, the quorum is essential for ensuring that critical services can continue operating even if some nodes fail. The cluster requires a majority of nodes to be operational to make decisions and maintain service availability. If the required quorum cannot be achieved, the cluster will not form or may enter an unavailable state.

Is This Error Critical?

Yes, this error is critical as it directly impacts the ability of the cluster to function properly. Without a quorum, services hosted on the cluster may fail, leading to potential downtime and loss of availability for applications relying on these services.

How to Diagnose

  1. Review Node Status: Verify that all required nodes are operational and communicating with each other.
  2. Check Network Connectivity: Ensure there are no network issues preventing communication between nodes.
  3. Verify Configuration Settings: Confirm that the quorum configuration settings meet the requirements for your cluster environment.
  4. Monitor Resource Availability: Check if resource limitations, such as CPU or memory, are affecting node availability.

How to Resolve

  1. Restart Failed Nodes: If nodes have failed, restart them and ensure they join the cluster successfully.
  2. Resolve Network Issues: Address any network connectivity issues that may be preventing communication between nodes.
  3. Adjust Quorum Settings: Modify quorum settings if necessary to meet the requirements for your specific environment.
  4. Increase Resource Availability: Ensure there are sufficient resources available on all nodes to meet the quorum requirement.

Developer Notes

Developers should ensure that their applications and services are designed to handle potential cluster failures gracefully, including scenarios where a quorum cannot be achieved. This includes implementing failover strategies and ensuring that critical data is replicated across multiple nodes to maintain availability even in the event of node failures.

Related Errors

  • ERROR_CLUSTER_NODE_DOWN (5926): Indicates that a required node has failed or is not responding.
  • ERROR_NETWORK_SUBSET_FAILURE (5930): Indicates network connectivity issues preventing communication between nodes.
  • ERROR_QUORUM_NOT_AVAILABLE (5941): Indicates that the quorum configuration settings are incorrect or insufficient to form a cluster.

FAQ

Q: What does ERROR_CLUSTER_NO_QUORUM mean?

A: It indicates that the required quorum of nodes in a Windows Failover Cluster is not present, preventing the cluster from forming or operating correctly.

Q: How can I prevent this error?

A: Ensure all required nodes are operational and communicating with each other. Verify network connectivity and configuration settings to meet quorum requirements.

Q: Can this error be resolved by restarting nodes?

A: Yes, restarting failed nodes may resolve the issue if they were down or not responding.

Summary

The ERROR_CLUSTER_NO_QUORUM error is a critical indication that the required quorum of nodes in a Windows Failover Cluster is not present. This can lead to cluster unavailability and service downtime. By understanding the causes, diagnosing the issue, and taking appropriate actions, you can ensure the reliability and availability of your clustered services.