NetWorker : Windows FS Backup fails with error read failed-volsnap

Summary: Windows File System Backup fails with error read failed and unrecoverable read file - volsnap event

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.

Symptoms

Backup fails for E:\  drive on a Windows client after running for some hours. No issue with backup for other drives or DR save set.
Error messages in Workflow logs:

--- Job Indications ---
read failed on \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy15\<file with path>: No such file or directory.

Error messages in action logs (/nsr/logs/policy/<policy>/<workflow>/<backup_xxx_logs>/xxx.log):

91579:save: Unrecoverable readfile error captured, backup will not complete.
127945:save: read failed on \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy15\<file with path>: No such file or directory

Cause

Shadow copy gets created while starting backup but removed before backup completion due to volsnap event .
Windows system event log ID 25.

The shadow copies of volume E: were deleted because the shadow copy storage could not grow in time.  Consider reducing the IO load on the system or choose a shadow copy storage volume that is not being shadow copied.

Windows Storage controller driver and firmware were not updated and there was another local backup used to run on the E:\ drive during NetWorker backup. However, updating driver/firmware and changing NetWorker backup start time after local backup completion didn't resolve the problem.
 

Resolution

The drive size was around 7TB with 2.3 TB of free space. The storage for the shadow copy was set to 700GB.
The issue was resolved after increasing the shadow copy storage to 1.2TB

Additional Information

Affected Products

NetWorker
Article Properties
Article Number: 000217935
Article Type: Solution
Last Modified: 06 Jan 2026
Version:  1
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