System State policy not backing up due to incorrect VSS permissions

VSS (Volume Shadow Copy Service, or Volume Snapshot Service), is a technology included in Microsoft Windows that allows taking manual or automatic backup copies or snapshots of computer files or volumes. The VSS captures and copies stable images for backup on running systems, particularly servers, without unduly degrading the performance and stability of the services they provide.

Important Note:
As part of the Microsoft Windows server operating system, VSS is not a product provided by Cloud Direct. This article is intended as a first step to help resolve VSS related issues affecting Cloud Direct's backup service. However, should VSS-related problems persist then please contact your local IT Support.

LiveVault relies on one of the Windows VSS writers (the System writer) to produce a System snapshot. This is then backed up by the LiveVault System State policy. If LiveVault cannot back up the System State, then it is possible that the VSS writers do not have correct permissions to enable the System writer and so produce a System snapshot. This article describes how to:

  • Check the VSS writers to determine if a problem exists,
  • Apply correct permissions to enable the System writer.

Checking the VSS writers

Check the VSS writers by examining the vssadmin list writers log as follows.

  1. Open a Command Prompt (CMD) window:
    1. With Windows 8, 8.1, or 10, right click on the Start button, then select Command Prompt (Admin) from the menu options.
    2. With Windows 7, Vista, or XP, click Start>All Programs>Accessories>Command Prompt).

You must open the CMD window as an administrator.

  1. If a User Account Control dialogue box appears, click Yes.

An Administrator: Command Prompt window appears.

  1. At the Command Prompt, type, vssadmin list writers, then press Return.

The screen lists vssadmin writer data, then stops at another prompt.

  1. Scroll back through the list of VSS writers, looking for the System writer.

If you don't see System writer in the list, then you need to apply correct permissions to enable the System writer.


Applying correct permissions to enable the System writer

To apply the correct VSS permissions to enable the System writer, and so allow the System State policy to be backed up, proceed as follows.

  1. Open a CMD (administrator) window, and run the following command.
    1. Type, Takeown /f %windir%\winsxs\filemaps\* /a
    2. Press Return.
    3. Type, icacls %windir%\winsxs\filemaps\*.* /grant "NT AUTHORITY\SYSTEM:(RX)"
    4. Press Return.
    5. Type, icacls %windir%\winsxs\filemaps\*.* /grant "NT Service\trustedinstaller:(F)"
    6. Press Return.
    7. Type, icacls %windir%\winsxs\filemaps\*.* /grant BUILTIN\Users:(RX)
    8. Press Return.

This command  enables the System writer, which will now show on the list of vssadmin writers.


Retry the System State backup to ensure that it now works correctly.