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AhsayOBM File backup fails: Shadow Copy snapshot missing

June 2, 2025

Product Version

AhsayOBM/AhsayOBM: 7.5.0.0 to 7.x

Operating System

Windows

Symptom

When perform a file backup up on AhsayOBM/AhsayACB v7 the job ends with "Snapshot for Shadow Copy Set is missing, backup terminate." error.

No.TypeTimestampLog
*.........
*erroYYYY/MM/DD hh:mm:ssSnapshot for Shadow Copy Set is missing, backup terminate.
*info......

Cause

The error message is returned by the Microsoft Windows Volume Shadow Copy Service (VSS).

To support backups of volume mount points on Windows file backup sets on AhsayOBM/AhsayACB v7, if "Volume Shadow Copy" option is enabled , AhsayOBM/AhsayACB v7 will initiate a VSS snapshot of all local drives found on the machine regardless if the drive has been selected in the backup source.

This behavior different from AhsayOBM/AhsayACB v6 which only initiates a VSS snaphot of a local drive selected in the backup source.

Resolution

If the client machines are not configured with volume mount points and there are persistent "[Shadow Copy] Snapshot for Shadow Copy Set is missing, backup terminate." backup errors.

As a workaround you could consider reverting the current AhsayOBM/AhsayACB v7 VSS snapshot behaviour back v6, this can be done by:

  1. Editing the %OBC_INSTALLL_PATH%\ cb.opt file

    Example:

    # Set option to true for disabling adding all volumes to shadow copy set
    com.ahsay.obx.core.backup.file.ShadowCopy.disableAddAllVolumes=true
    
  2. Restart AhsayOBM/AhsayACB scheduler service.