Issue
Backups for a protected endpoint surface a warning or fail with the error message, "Error 327: VSS Writer Error."
Environment
NinjaOne Backup
Cause
A Volume Shadow Copy Service (VSS) writer is in an unhealthy state. The name of the VSS writer will appear in the error details.
When NinjaOne Backup initiates a disk volume backup, it creates a Volume Shadow Copy Snapshot. Creating the snapshot triggers the Volume Shadow Copy Service (VSS) to call any associated VSS writers needed to capture a stateful image of the protected drive. If a VSS writer encounters an error during the backup process, the job may continue, but unresolved errors could compromise restore consistency.
Resolution
Troubleshooting steps will differ depending on the failed VSS writer.
All VSS writers are associated with a Microsoft Windows service. Restarting the service with the failed writer can help.
You can also use VSSADMIN to review the endpoint's VSS writer configuration. To learn more about this process, refer to vssadmin | Microsoft Learn (external link).
If the issue persists, our Technical Support team can provide additional troubleshooting.
Additional Resources
For additional troubleshooting guidance, refer to NinjaOne Backup: Troubleshooting Error Codes.