Fix ERROR_QUORUM_RESOURCE (0X0000139C) on Windows Cluster

Quick answer: Move the quorum resource to another disk first using Move-ClusterQuorum or the Failover Cluster Manager GUI. Then you can delete or offline the original disk.

I know this error grabs your attention: you're trying to remove a shared disk from your cluster, and suddenly you get ERROR_QUORUM_RESOURCE (0X0000139C). The server just says no. This happens because the disk you're touching holds the quorum witness — it's the tie-breaker for your cluster. Windows won't let you kill it while it's still the quorum. I ran into this a lot at my old support job, usually when someone was decommissioning a disk or rebuilding storage. The fix isn't complicated, but you need to be careful.

Why You See This Error

The cluster has a quorum resource that keeps everything running: if servers lose contact, the quorum decides which side stays alive. You can't delete or offline that resource because it would break the quorum setup. The error pops up when you try to remove the disk or take it offline in Failover Cluster Manager. Common trigger: you're cleaning up old disks after a storage migration on Windows Server 2019 or 2022.

How to Fix It

Stop trying to delete the disk directly. You need to move the quorum role to another disk first. Here's the step-by-step. Skip anything that says 'just force delete' — that'll crash your cluster.

Step 1: Identify the quorum resource

1. Open Failover Cluster Manager.
2. Go to your cluster, click Roles.
3. Find the disk that's the quorum — it's usually listed under Storage. Right-click it and check properties. Look for the 'Quorum' tab.

Or use PowerShell to see exactly which resource has the quorum role:

Get-ClusterQuorum

This shows you the quorum type and the resource name. Write that name down.

Step 2: Add a new disk to the cluster

If you don't have a spare disk in the cluster, add one. Connect a new disk (or volume) to all cluster nodes, then in Failover Cluster Manager go to Storage > Disks > Add Disk. Choose the new disk. Wait for it to come online.

Step 3: Move the quorum to the new disk

This is the real fix. Use the GUI: right-click your cluster name, select More Actions > Configure Cluster Quorum Settings. Follow the wizard and select the new disk as the quorum witness. Or do it faster with PowerShell:

Move-ClusterQuorum -Name "NewDiskName"

Replace NewDiskName with the actual disk resource name you added. This changes the quorum to the new disk instantly.

Step 4: Verify the quorum moved

Run Get-ClusterQuorum again. You should see the new disk listed. The old disk is now free.

Step 5: Delete or offline the old disk

Right-click the old disk in Failover Cluster Manager and choose Remove or Take Offline. The error should be gone. It worked for me every time.

Alternative Fixes If the Main One Fails

Sometimes the disk you want to add is busy or not available. Here's what else you can try:

• Use a file share witness: If you can't add a new disk, change the quorum to a file share. Right-click the cluster, More Actions > Configure Cluster Quorum Settings, choose the file share witness option. Point it to an SMB share on a separate server. Once done, the original disk is no longer the quorum and you can delete it.
• Set quorum to None (temporary): This is risky. Only do this if you're sure the cluster is stable and you'll fix it right after. Run Set-ClusterQuorum -NoWitness in PowerShell. Then delete the disk. Then add a new quorum witness immediately. I don't recommend this for production — you lose the tie-breaker.
• Check if the disk is still in use: Sometimes other roles or applications use the same disk. Look in Roles for any dependencies. Move those roles to another disk first.

Prevention Tips

To stop this error from biting you again, plan your storage changes. Before you remove any cluster disk, check its quorum status with Get-ClusterQuorum. Always keep at least one spare disk in the cluster for quorum moves. If you're using a disk witness, document which disk it is. I've seen admins kill their cluster by deleting the wrong disk — don't be that person. Also, set regular reminders to audit your quorum configuration. A quick monthly check saves you a headache.