Virtualization, Servers and Storage : UTORrecover - NetWorker Windows Client Backup – pseudo_saveset / VSS Errors

Created by JM Lopez, last modified on Nov 21, 2025

(blue star) Problem

  1. Typical symptoms include:

    • A backup job on the Windows client fails when attempting to process the pseudo_saveset. 

    • Example log entries: 

      181407:save: Step (1 of 5) for PID-8600: Save has been started on the client '<client_name>'.
174412:save: Step (2 of 5) for PID-8600: Running the backup on the client '<client_name>' for the save set 'pseudo_saveset'.
174424:save: Step (3 of 5) for PID-8600: Creating the snapshot for the selected save sets.
VSS OTHER: ERROR: VSS failed to process snapshot: Unable to create the VSS snapshot.
197048:save: Unable to save the SYSTEM STATE save sets and create the snapshot: Unable to create the VSS snapshot.

  2. Unable to create the VSS snapshot.

While this is one concrete error message, the issue may occur with other VSS-related error messages too (the root cause and resolution steps remain similar).

(blue star) Cause

The underlying cause is a problem with the Windows Volume Shadow Copy Service (VSS) on the client system. VSS is the technology used by NetWorker (and other backup software) to create consistent snapshots of volumes for backup. 

Typically, issues arise due to:

  • Operating system misconfiguration, corruption or a bad patch applied which has impacted VSS functionality. 

  • VSS writers or shadow copies being in a bad state on the client machine.

  • Other software (e.g., third-party snapshot/backup agents) interfering with VSS operations.

(blue star) Solution

On the client: 

  1. Open an Administrator command prompt and stop the NetWorker client:

net stop nsrexecd /y

  1. Kill any NetWorker services which did not stop:

taskkil /F /IM nsr*

  1. Kill any NetWorker backup processes which did not stop:

taskkill /F /IM save* 

  1. Rename the C:\Program Files\EMC NetWorker\nsr\logs\daemon.raw

  2. Remove the C:\Program Files\EMC NetWorker\nsr\tmp (any renamed /tmp directories also).

  3. In Services (services.msc), locate the Volume Shadow Copy service:

    • Stop the service

    • Then Start the service

  4. Start NetWorker client services again:

net start nsrexecd

  1. Test a small backup excluding VSS

If this succeeds, then a workaround is available but involves our team. Update the ticket or reach out to us via https://utor.cloud/utorrecover/help

Gather additional VSS diagnostics

To assist with root-cause analysis, run these commands on the client:

vssadmin list writers
vssadmin list shadows

Recommended Best Practices & Notes

  • Always ensure Windows updates and patches do not interfere with VSS. If a patch caused the issue, consider rolling back or applying follow-up fixes.

  • Avoid running multiple backup or snapshot agents on the same system unless they are explicitly designed to co-exist with VSS.

  • Regularly monitor the health of VSS writers and shadow storage usage on Windows clients.

  • If VSS issues recur, engage Microsoft support for deeper investigation of the OS environment.

  • While disabling VSS may allow backup to proceed, it prevents true application-consistent snapshots for e.g., SQL/Exchange/System State. Use with caution and ensure you understand the implications.

References