Avamar: Hyper-V backups fail with "Failed to get the HA VMs"

Summary: Hyper-V backups using Avamar may fail when the Avamar Windows Cluster Service cannot retrieve clustered virtual machines. This issue often occurs in multi-proxy configurations or when cluster resources are misconfigured. ...

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Symptoms

Hyper-V backups fail with errors similar to: 
Error <17211>: Failed to get the HA VMs from the Avamar Windows Cluster Service, Err = 80004005
Error <17203>: unable to prepare VMs for backup
Error <17179>: Failed to get the virtual machines from the Avamar Windows Cluster Service
Additional log entries may include: 
GetWmiConnection : Invalid parameter
Could not query clustered VMs. Failing multi proxy backup
Multi proxy backup did not complete successfully
One or more VMs specified in the dataset may have been removed from the cluster.

Cause

Several factors can contribute to this issue:

  1. WMI or PowerShell services are in a failed or unresponsive state.
  2. Permissions issue: The account used by the Avamar Windows Cluster Service lacks access to Hyper-V namespaces.
  3. Incorrect multi-proxy configuration: Multiple nodes are set as primary proxies, or secondary nodes contain the --proxy flag in avhypervvss.cmd.
  4. Dataset misconfiguration: A VM listed in the dataset no longer exists in the cluster.

Resolution

  1. Validate WMI connectivity:
    Run this command in PowerShell: 
    • Get-WmiObject -Query "Select * From mscluster_resource where Type='Virtual Machine'" -Namespace root\mscluster

If the command fails, reboot the Hyper-V node to restore WMI functionality.

  1. Verify permissions:
    • Add the domain account (used by the Avamar Plug-in Service) to:
      • Local Administrators
      • WinRMRemoteWMIUsers groups on each cluster node
    • Confirm that the account is a member of Domain Admins in Active Directory.
    1. Correct multi-proxy configuration:
      • Only the primary node should have: 
        • --multi-proxy=node1,node2,node3,node4
--proxy
      • Remove any proxy settings from avhypervvss.cmd on secondary nodes.
    2. Update dataset:
      • Remove any VM that no longer exists in the cluster
      • Verify VM status in Failover Cluster Manager.

      Additional Information

      Additional Information

      • Applies to Avamar Hyper-V backups in clustered environments
      • If the issue persists after these steps, collect logs and contact Dell Support

      Affected Products

      Avamar, Avamar Plug-in for Hyper-V VSS
      Article Properties
      Article Number: 000039412
      Article Type: Solution
      Last Modified: 05 Dec 2025
      Version:  5
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