4729: Acronis Backup & Recovery 10: Using Microsoft VSS instead of Acronis VSS

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Last update: 26-07-2011

Instructions on how to enable Microsoft native VSS instead of the default Acronis VSS in Acronis Backup & Recovery 10

This article applies to:

  • Acronis Backup & Recovery 10 Advanced Server
  • Acronis Backup & Recovery 10 Server for Windows (Standalone)
  • Acronis Backup & Recovery 10 Advanced Server - Small Business Server Edition
  • Acronis Backup & Recovery 10 Advanced Workstation
  • Acronis Backup & Recovery 10 Advanced Server - Virtual Edition

(!) If you are using Acronis Backup & Recovery 11, see Acronis Backup & Recovery 11: Using Microsoft VSS instead of Acronis VSS.


By default, Acronis Backup & Recovery 10 uses Acronis VSS Provider which interacts with Microsoft VSS to create volume shadow copies of the data, however the actual VSS snapshot created by Microsoft VSS is not used (Acronis Backup & Recovery 10 uses its own snapshot).

Here is the step-by-step description of how the backup is made with the VSS support option enabled:

  1. Acronis Backup & Recovery 10 initiates VSS snapshot. This snapshot is created by MS VSS service via Acronis VSS provider, which is in fact a 'fake' VSS provider. Acronis Backup & Recovery 10 must start VSS snapshot creation through Acronis VSS provider to capture the moment when all VSS writers freeze and databases are ready for backup. This is the only purpose of Acronis VSS provider, i.e. VSS snapshot created in this step is not used at all and is in fact a 'fake' one. It was necessary to create this 'fake' VSS provider because MS VSS service does not have API functions to freeze VSS writers directly;
  2. Acronis Backup & Recovery 10 sends a request to MS VSS service to suspend VSS writers;
  3. Acronis Backup & Recovery 10 creates a simple snapshot (not a VSS snapshot; See SnapAPI). This snapshot is created when all writers freeze and databases are ready to be backed up;
  4. Acronis Backup & Recovery 10 aborts VSS snapshot initiated by MS VSS, as this snapshot is not necessary. This may result in errors in the Windows Event logs, which can be safely skipped;
  5. Acronis Backup & Recovery 10 initiates a backup through the simple snapshot created in step 3.

See below for instructions on how to enable native Microsoft VSS snapshot support, which is also included in the product. (This snapshot by default is ignored by the backup process as described above).


(!) With the native Microsoft VSS enabled as described below, the Acronis SnapAPI driver does not take any part in the backup process. The snapshot is done by the Microsoft VSS. All issues with the backup, if any, are a part of the Microsoft VSS implementation.

  • Open Windows Registry Editor (Start-Run, type in regedit);
  • Navigate to the following registry key (if it is not present, create it):

    Windows 32-bit: HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\BackupAndRecovery\Settings\DiskManager

    Windows 64-bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Acronis\BackupAndRecovery\Settings\DiskManager

  • Under the \DiskManager\ key create a new DWORD value with the UseNativeVssProvider name (note the CamelCase). Set the value of the created UseNativeVssProvider entry to "1":

  • Restart Acronis Managed Machine Service:
    • Hit Start-Run and type in services.msc;
    • Right click on Acronis Managed Machine Service and select Restart.
  • Run Acronis Backup & Recovery 10 Management Console and create a new backup task with the VSS option enabled:

    (!) It is necessary to create a new backup task to apply the option properly.

As the result, the native Microsoft VSS snapshot creation will be forced and used during the backup process. Thus, if Microsoft VSS itself is functioning properly on the server, then the backup task will run properly.

More information

See also Microsoft TechNet Article: What Is Volume Shadow Copy Service?