Source:Troubleshooting VSS

From SEPsesam

Volume Shadow Copy Service (VSS)

SEP sesam uses Microsoft’s Volume Shadow Copy Service (VSS) to perform backups for various task types. It uses only the VSS components, provided by Microsoft. VSS failures are typically caused by the system configuration and not by SEP sesam. Note that VSS has some restrictions and limitations. For more detailed information on VSS, see the article Volume Shadow Copy Service from Microsoft.

This section provides only limited guidance for most common VSS issues. For more specific and difficult cases, refer to Microsoft support (KB).

Common VSS problems

Follow the instructions below if you encounter a VSS error. After each step, run a test to make sure that the problem has been fixed.

1. Backup is failing with a 10054 error. The event viewer shows the error: Cryptographic Services failed while processing the OnIdentity() call in the System Writer Object.


  • The VSS backup on Windows 10 or 2012/R2 fails with an error. The backup log shows:
Info: Backup finished. Status: ERROR Data sending failed. (10054) An existing connection was forcibly closed by the remote host.

More detailed information about the cause of the error can be found in the application event log:

Cryptographic Services failed while processing the OnIdentity() call in the System Writer Object.
AddLegacyDriverFiles: Unable to back up image of binary Microsoft Link-Layer Discovery Protocol.
System Error:
Access is denied.


  • The MSLLDP driver's security permissions do not allow NETWORK_SERVICE to access the driver record. This can cause the backup process to hang for a long time or fail.


  1. Open an administrative command prompt (NOT PowerShell) and execute the following command as one long command without carriage returns (do not move the cursor to the beginning of the line):
  3. If you get a successful result, e.g., [SC] SetServiceObjectSecurity SUCCESS, the problem is solved. Otherwise, reboot your Windows system.

2. Windows reboot


  • Reboot your Windows. A Windows reboot often eliminates various VSS writer problems.

3. Disk space


  • If there is insufficient disk space, VSS snapshots may fail.


  • Make sure that sufficient disk space is available.

4. Multiple backup jobs with VSS


  • If multiple VSS jobs are started, the operating system reports the following VSS error message:

Possible causes

  • It is not possible to run multiple VSS snapshots at the same time. Windows can only start a VSS snapshot for each partition.


  • Run the backup jobs from a client sequentially, for example:
    • 22:00: Start System Recovery Backup
    • 23:00: Start Custom Path Backup.
  • If the temporal separation is not possible, try the following solution. These must be set in the following sm.ini settings on the client:
With these settings, the VSS sesam client tries to execute operations sequentially and waits for an active VSS operation. The matching settings may vary depending on the system and backup jobs.

5. Third-party backup software


  • Check if some other backup software from another vendor is running on the system, for example:
    • Windows Backup, NTbackup
    • Acronis, Backup Exec, etc.

Disable this backup software if necessary.

6. Remove old VSS snapshots


  • Start the command prompt (CMD) as administrator and enter the following command:
vssadmin delete shadows /all

The command deletes all VSS snapshots of all volumes.

7. VSS writer status check


  • Start the command prompt (CMD) as administrator and enter the following command:
vssadmin list writers
  • If a VSS writer error appears, restart the following services:
    • Volume Shadow Copy Service
    • VSS application writer (Exchange, MS-SQL, Hyper-V)
    • COM+ System Application Service
    • Distributed Transaction Coordinator Service
  • Run the command vssadmin list writers again and check if the problem is fixed.

8. Windows event log check


  • Check the event logs of the Windows Event Viewer. Search for VolSnap errors corresponding to VSS at the time of the SEP sesam backup job.
  • It often helps to search the internet for the event ID of the error to get an indication of the error cause.

9. Re-register VSS and COM+ components

Step 1:

  • The following scripts re-register all VSS and COM+ components.
  • Copy the commands into a new *.bat file. Start the batch script in the command line as administrator:

For 64-bit and 32-bit systems:

cd /d %windir%\system32
Net stop vss
Net stop swprv
regsvr32 ole32.dll
regsvr32 vss_ps.dll
Vssvc /Register
regsvr32 /i swprv.dll
regsvr32 /i eventcls.dll
regsvr32 es.dll
regsvr32 stdprov.dll
regsvr32 vssui.dll
regsvr32 msxml.dll
regsvr32 msxml3.dll
regsvr32 msxml4.dll
regsvr32 Vssapi.dll
regsvr32 Vssui.dll
net start vss
net start swprv

Step 2:

  • Copy the commands into a new *.bat file. Start the batch script in the command line as administrator:

For 64-bit systems:

Net stop vss
Net stop swprv
regsvr32.exe /i %windir%\system32\eventcls.dll
regsvr32.exe /i %windir%\system32\swprv.dll
regsvr32.exe %windir%\system32\vssui.dll
regsvr32.exe %windir%\SysWOW64\vss_ps.dll
regsvr32.exe %windir%\SysWOW64\msxml.dll
regsvr32.exe %windir%\SysWOW64\msxml2.dll
regsvr32.exe %windir%\SysWOW64\msxml3.dll
regsvr32.exe %windir%\SysWOW64\msxml4.dll
regsvr32.exe %windir%\SysWOW64\ole32.dll
regsvr32.exe %windir%\SysWOW64\oleaut32.dll
regsvr32.exe %windir%\SysWOW64\es.dll
regsvr32.exe %windir%\SysWOW64\comsvcs.dll
vssvc /register
net start swprv
net start vss
net stop winmgmt
regsvr32 wmiutils.dll  
net start winmgmt 

10. VM utility update


  • If the system is a virtual machine, uninstall the installed utility version, start the VM, and then reinstall the latest VM utility version:
    • VMware vSphere: VMware Tools
    • Microsoft Hyper-V: Hyper-V Integration Services
    • Citrix XenServer: XenServer Tools

11. Windows update


  • Install the latest Windows updates, service packs and hot fixes from Microsoft.
  • Run a test after the update.

VSS backup fails with VSS error

If a VSS error occurs when backing up your Windows client, you need to find out the cause. Open the Windows Event Viewer and check the relevant logs. These errors can be any of the following:

You may receive similar error messages and/or aborted backups if you try to perform a VSS backup on volumes larger than 64 TB, even if the volumes are excluded from the backup. Note that writable snapshots or snapshots larger than 64 TB produce the same error.

Microsoft states the limitation of "64 TB" in the article Usability limit for Volume Shadow Copy Service (VSS) in Windows.

The above errors can be caused by any of the following:

Problem 1

  • When trying to perform a VSS backup with volumes larger than 64 TB on a Windows server, you get the following error:
"DB Module: [ [NInternal::CVssAsyncDecorator::Wait] - S_OK]"

and the Windows event logs show a VSS event ID 12289



  • Microsoft has a restriction of 64 TB as the maximum size for volumes when performing backups with VSS. It is not possible to use VSS for larger volumes, even if they are excluded from the backup.


  • Enable the Volume Shadow Copy Service for all drives: Right-click on any of the listed Hard Disk Drives and click Configure Shadow Copies. In the Shadow Copies window, click Enable and then enable shadow copies for all drives.

Problem 2

  • When trying to perform a VSS backup of a volume larger than 60 TB or when you create VSS backups of multiple volumes in Windows Server 2008/Windows Storage Server 2008, the VSS backup fails with the following message:
ERROR: [CVssServer::CreateSnapshot(): IVssBackupComponents::DoSnapshotSet: WaitForAsyncOperation] - VSS_E_PROVIDER_VETO 

Possible causes

  • As already explained (see above note), Microsoft has set a usability limit for volumes and snapshots with VSS.
  • This error can also occur if a VSS provider blocks snapshot creation for the following reasons: Software has been installed with its own VSS provider or the existing VSS component is corrupted.
  • HP Device Access Manager (FLCDLOCK service; part of the HP Protect Tools suite) prevents VSS operations from properly accessing drive partitions.


  • Due to the limitation within volsnap.sys, do not use volumes larger than 60 TB as a backup source or destination for Windows backups.
    • Remove volumes larger than 60 TB from the VSS snapshot action.
    • Reconfigure all disks with a current size larger than 60 TB to 60 TB or less to prevent VSS from stopping when the snapshot is created.
    • Also check the size of the shadow storage on the respective drives and increase it (if necessary). Use the Vssadmin command-line tool from an elevated command prompt (where c: should be replaced with the correct drive):
vssadmin Resize ShadowStorage /For=C: /On=C: /Maxsize=5%
  • Fix the VSS problems and then re-register the VSS components. Additionally, check the size of the shadow storage on the drives in question and increase it (if necessary) with the Vssadmin command-line tool, as described in the previous solution.
  • Uninstall HP Device Access Manager and restart your system. Note that incomplete uninstallation of HP Device Access Manager may cause problems.

You can use a third-party removal tool to correctly and completely uninstall Device Access Manager for HP ProtectTools. For details, see the article How to uninstall Device Access Manager for HP ProtectTools?.

The link provided will take you to a third party website. SEP provides such links for informational purposes only and is not responsible for the information, availability or accuracy of these external resources.

Problem 3

  • VSS Path backup from a Windows Storage Spaces volume fails with error:
Error:   DB Module: [ [CVssServer::WaitForAsyncOperation: IVssAsync::QueryStatus] - VSS_E_PROVIDER_VETO]


  • VSS snapshots are not supported for Windows Storage Spaces.


  • To back up data from Windows Storage Spaces volumes, you have to disable the option Backup with VSS (enabled by default) in the backup task properties. For details, see Disabling/enabling VSS-based backups.
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