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Cannot create quiesced snapshots if backup or system recovery applications are installed (1009558)

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When creating virtual machine backups using quiescent snapshots, you experience these symptoms:
  • The Create Virtual Machine Snapshot task either times out or remains indefinitely. The snapshot and virtual machine snapshot delta disks are not created.

  • After attempting to create a snapshot, the virtual machine is unable to respond to other tasks or requests and reports:

    Another operation is in progress.

  • You see the error:

    Protocol error from VMX

  • While the Create Virtual Machine Snapshot is pending, the vmware.log file for the virtual machine shows continued logging:

    vcpu-0| TOOLS: backup event set in VMDB (req.keepAlive 0 )
    vcpu-0| TOOLS: backup event set in VMDB (req.keepAlive 0 )
    vcpu-0| TOOLS: backup event set in VMDB (req.keepAlive 0 )
    vcpu-0| TOOLS: backup event set in VMDB (req.keepAlive 0 )
    vcpu-0| TOOLS: backup event set in VMDB (req.keepAlive 0 )

  • The hostd log file for the respective ESX host logs events indicating that the event queue is full. For example:

    F6468B90 warning 'vm:/vmfs/volumes/4a68bc23-4510a5f3-83b1-00145ea82142/VM-ACSrv1/VM-ACSrv1.vmx'] BackupAgentImpl: evicting event due to full queue (keepAlive)
    F63A5B90 warning 'vm:/vmfs/volumes/4a68bc23-4510a5f3-83b1-00145ea82142/VM-ACSrv2/VM-ACSrv2.vmx'] BackupAgentImpl: evicting event due to full queue (keepAlive)
    F6364B90 warning 'vm:/vmfs/volumes/4a35051f-40bf72e2-d504-00145ea82790/VM-SySrv2/VM-Srv2.vmx'] BackupAgentImpl: evicting event due to full queue (keepAlive)
    F6468B90 warning 'vm:/vmfs/volumes/4a68bc23-4510a5f3-83b1-00145ea82142/VM-SynDC1/VM-DC1.vmx'] BackupAgentImpl: evicting event due to full queue (keepAlive)
    F66136D0 verbose 'vm:/vmfs/volumes/4a68bc23-4510a5f3-83b1-00145ea82142/VM-KlicSrv1/VM-Srv1.vmx'] Quiesced snapshot backup agent event: (vim.vm.BackupEventInfo) {
       dynamicType = <unset>,
       eventType = "keepAlive",
       code = 0,
       message = "",


Installations of VMware Tools for virtual machines running on VMware ESX 3.5 Update 2 and later include the VMware Volume Shadow Copy Service (VSS). This service is required for effective quiescent snapshots in VMware vSphere or Infrastructure without relying on the VMware File Sync Driver.

However, third-party and partner VSS providers (if present in the guest operating system) conflict with the VMware Volume Shadow Service provider.

These additional VSS providers are commonly included with other backup products, such as Symantec System Recovery or BackupExec.

In most cases, these additional providers are not required if you are relying on VMware Consolidated Backup (VCB) or VMware Data Recovery (VDR) to perform virtual machine backups, and can be removed to resolve the issue.

If these providers are required in the guest operating system, however, remove the VMware VSS component from your VMware Tools installations in the affected guest systems. This forces VCB and VDR to use the "File Sync Driver" for quiescent snapshots, instead of VSS.

Note: A power cycle of the virtual machine is required to clear the Protocol error from VMX error. If the virtual machine cannot be powered down due to tasks in progress, restart VMware Tools in the guest operating system and restart the management services on the ESX host hosting the virtual machine.

For more information, see Restarting the Management agents on an ESX or ESXi Server (1003490).

Additional Information

If you are using Symantec products in the affected guest operating system, see Compatibility of the Backup Exec Agent for VMware Virtual Infrastructure (AVVI) Symantec VSS Provider (BEVSSProvider) with the VMware VSS Provider for additional information and documents on this issue.

In Windows 2008 operating systems, the Volume Shadow Copy Service (VSS) is installed as part of the operating system and VMware Tools does not install VSS in Windows 2008.

To view a list of registered VSS providers for a Windows guest operating system, open a command prompt and run this command:
# vssadmin list providers
For more information on the vssadmin command, see the Microsoft article, Vssadmin list providers.

Note: The preceding links were correct as of September 17, 2013. If you find a link is broken, provide feedback and a VMware employee will update the link.

See Also

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


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  • 19 Ratings