SIRIS, ALTO, and NAS: Error: Backup failed due to a problem with incremental tracking



When you try to start a backup for a system protected by the ShadowSnap agent, you receive the error message, "Backup failed due to a problem with incremental tracking."

In legacy versions of the Datto IRIS environment, this error message was "GUID mismatch."


  • ShadowSnap Agent


  • ShadowSnap is unable to continue to the next incremental because the StorageCraft journal numbers became out of sync.
  • Volumes of the drives are in states that ShadowSnap cannot read properly.
  • The agent was rebooted in the middle of a backup
  • A backup was interrupted mid-transfer before completion due to a dirty shutdown of the ShadowSnap services on the protected system
  • Separately created ShadowProtect jobs are configured on the target agent, interfering with the incremental tracker used by ShadowSnap.
  • A RoundTrip drive may improperly interrupt the backups and journaling numbers. This can result in all agents requiring diff-merges.
    • RoundTrip error codes and messages may vary in appearance, including "invalid data format," "GUID mismatch," and write errors.  


1. Make sure that the protected server's ShadowSnap software is updated to the latest version.

2. Check to see if any ShadowProtect backup jobs are present, as shown in Figure 1. If there are, disable or remove the jobs.

Figure 1: ShadowProtect backup jobs (click to enlarge)

3. ShadowSnap and ShadowProtect use the same incremental tracker. After you confirm that the ShadowSnap Agent is updated to the latest version, force a differential merge through the ProtectConfigure Agent SettingsAdvanced section of the Datto appliance's device GUI.

Figure 2: Force Differential Merge (click to enlarge)

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