App-aware Backups of a Virtual Machine Failing


To inform users regarding failure of App-aware Incremental Backups due to snapshot issues.


Full Backups of a Virtual Machine (VM) with App-aware ON, work correctly. However, Incremental Backups of the VM with App-aware OFF encounter failures.

The error messages seen in the Backup messages is something like –

Backup failed: Error creating snapshot of VM: GenericVmConfigFault: An error occurred while saving the snapshot: Failed to quiesce the virtual machine.

SOAP Fault:


Fault string: An error occurred while saving the snapshot: Failed to quiesce the virtual machine.An error occurred while saving the snapshot: Failed to quiesce the virtual machine.

Fault detail: GenericVmConfigFault

----- End VProtect Messages ----

Rebooting the VM doesn’t solve the issue


  1. First step is to try to uninstall and reinstall VMware Tools and then reboot the VM. Now perform new Full and Incremental Backups
  2. If this doesn’t succeed, then follow the steps in the following VMware KB –


Third-Party Sources


This happens due to issues with the VSS writers in the Windows guest itself, which might conflict with the other snapshot operations during Unitrends’ Backup.


For more detailed information on backup failures and performance issues see Unitrends KB 5062 - Backup Failures and Performance Issues

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