63806: Acronis Cyber Protect Cloud, Acronis Cyber Backup: Activity fails with "Operating system error: The shadow copy provider had an error"

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Last update: 29-04-2021


Backup activity fails with the following error:

Operating system error: The shadow copy provider had an error. Check the System and Application event logs for more information.


Acronis Cyber Backup utilizes Windows Volume Shadow Copy Service (VSS) writers to perform backups. VSS is a Windows operating system component that provides the functionality to take a snapshot of a volume. If VSS malfunctions at any step of snapshot creation, this will cause the snapshot failure and lead to backup errors, since Acronis Cyber Backup relies on successful snapshot creation by VSS for capturing data for backup.

This article provides guidance on how to troubleshoot VSS issues that cause Acronis backups to fail with volume snapshot-related errors.

If a VSS failure is detected that cannot be fixed using the recommendations from this article, the problem should be addressed to Microsoft and/or researched using their support resources. 


1. Download VSS Doctor to investigate and troubleshoot issues with VSS on the affected Agent machine

2. Check Windows Event log for VSS-related errors and fix the issues.

Open the Windows Event Viewer (press Win+R -> type eventvwr.msc) and check the Windows Logs, Application and System. Look for entries occurring around the time when the issue occurred or just before that.

3. If the issue persist after using VSS Doctor and Windows Event log does not contain any errors, follow the instructions in Acronis Cyber Backup: VSS Troubleshooting Guide to troubleshoot other possible issues with VSS,

If you perform an operation with a volume that is larger than 64 TB, the issue can be caused by usability limit for Volume Shadow Copy Service in Windows. See this article for more details.

If suggested steps did not help to localize the issue, collect the following information and contact Acronis Support:

  1. VSS Doctor report
  2. Acronis System information from the affected Agent machine: