VMware Cloud Foundation: Workaround for Quorum-Disk Failure Scenario in 2-Node WSFC 2025 Configuration

Synopsis
Broadcom has published a 10-minute demo video that shows you how to work around a commonly reported failure scenario in 2-node Windows Server 2025 Failover Clusters (WSFC) when adding/configuring a quorum disk in VMware Cloud Foundation (VCF).

Important: This video demonstrates a workaround for one symptom. It does not resolve the underlying WSFC 2025 defect that can present as broader quorum/core-resource transition and failover reliability issues.

Applies to
• Windows Server 2025 Failover Clustering (2-node)
• Shared disk / quorum disk configurations
• VMware Cloud Foundation deployments (symptoms also reported outside vSphere)

Customer-reported behavior (field symptom)
Customers have reported WSFC 2025 failure scenarios where expected quorum/core-resource behavior breaks down in a 2-node cluster. Broadcom has documented a related failure mode (where shutting down an active VM holding cluster resources when the cluster has no roles can lead to a cluster-down condition) and notes Microsoft is actively investigating.

Separately, similar 2-node quorum/ownership failure behavior is also described by customers in non-VCF environments (including 2-node configurations on Microsoft Hyper-V), confirming that the reported issues are not specifically hypervisor-related.

What we’re releasing
• A 10-minute demo video: This video shows a repeatable workaround to successfully complete quorum disk addition/configuration without triggering the Cluster failure condition.
• Scope: workaround for this specific symptom only – does not claim to “fix WSFC 2025.”

Microsoft mitigation (shipped update and enablement flag)
Microsoft has shipped Windows Server 2025 cumulative updates that customers commonly associate with the mitigation path, including KB5063878 (August 12, 2025; OS Build 26100.4946).

However, reports on Microsoft-hosted threads indicate the effective behavior may require an explicit FeatureManagement override registry value (2005146767) to be set (followed by a restart).

VERIFY THE UPDATE IS PRESENT (POWERSHELL)
GET-HOTFIX -ID KB5063878

ENABLE THE MITIGATION (CMD OR POWERSHELL, ELEVATED)
REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\POLICIES\MICROSOFT\FEATUREMANAGEMENT\OVERRIDES /V 2005146767 /T REG_DWORD /D 1 /F

DISABLE THE MITIGATION
REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\POLICIES\MICROSOFT\FEATUREMANAGEMENT\OVERRIDES /V 2005146767 /T REG_DWORD /D 0 /F

RETURN TO DEFAULT BEHAVIOR (REMOVE OVERRIDE)
REG DELETE HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\POLICIES\MICROSOFT\FEATUREMANAGEMENT\OVERRIDES /V 2005146767 /F

RESTART (REQUIRED)
RESTART-COMPUTER

Notes:
• If you are actively experiencing cluster instability during quorum disk configuration, you are encouraged to start with the workaround shown in this video, then evaluate Microsoft’s shipped mitigation and override flag in a controlled maintenance window.
• Community reports also describe broader “quorum/core resources don’t transition as expected” scenarios during node maintenance (including patching) in 2-node WSFC 2025.
• It’s important to note that the behavior described in this post and the accompanying video does not occur if you use a File Share Witness as the Quorum.

References
• Broadcom KB: WSFC 2025 2-node cluster-down scenario statement
• Microsoft Q&A: 2-node WSFC 2025 quorum owner restart causing cluster down
• Microsoft Q&A: Event 1177/quorum-loss thread incl. FeatureManagement override 2005146767
• Microsoft Support KB: KB5063878 (Windows Server 2025 cumulative update)