Basic Troubleshooting Guide for VSS – SAFE Backup

Basic Troubleshooting Guide for VSS – SAFE Backup

Disclaimer: VSS is an OS component, the steps mentioned below should only be performed by your system admin and/or after consulting Microsoft. We cannot take responsibility for faults caused by following the below steps.

This article provides the basic steps to resolve VSS issues before you address error messages or resort to more advanced troubleshooting.

Troubleshooting steps:
1. Check Windows event logs, both the application and system event logs for detailed VSS errors. Subsequently, also check the Hyper-V VMMS events.

2. Check third-party backup software for any third-party backup software. If found, uninstall it and reboot the server.

3. Check Shadow Storage Space on each server with the below command.
vssadmin list shadowstorage {/for=<ForVolumeSpec> | /on=<onVolumeSpec>}
Example: vssadmin list ShadowStorage /for=E:\

NOTE: If there is less shadow storage space allocated, increase the storage in accordance with the requirement or set it to unlimited.

vssadmin resize shadowstorage /for=<ForVolumeSpec> /on=<OnVolumeSpec> /maxsize=<MaxSizeSpec>
Example: vssadmin resize shadowstorage /For=E: /On=E: /MaxSize=UNBOUNDED

Delete any stale and old shadow copies using the following command:
Vssadmin delete shadows /all

4. Check Writers Status, VSS backups fail if application-specific writer, such as hyper-v writer or SQL, fails. Check the writer status with the following command:
Vssadmin list writers
This will list the writers and also show a status, below is an example of a failed report.
 

5. Troubleshoot unstable/failed writers using the following steps:
• Check the service account of the corresponding writer and ensure it is a system account.
• Check in the event log.
• Check the service of the corresponding writer. Restart the writer service and run the “vssadmin list writers” command again to see if this has resolved the issue.

6. Advanced troubleshooting steps for unstable/failed writers:
• Restart COM+ System Application Service
• Restart Distributed Transaction Coordinator Service
• Restart Volume Shadow Copy Service
• Restart the corresponding VSS writer service. For example, Hyper-V VSS writer or SQL VSS writer

7. Next you can re-register all VSS & COM+ components, run these individually in cmd, or create a batch file to run them:
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  
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

8. If using multiple providers, use an elevated cmd and run the following command:
vssadmin list providers
The output will list one or two providers:
Microsoft Software Shadow Copy Provider 1.0
Microsoft File Share Shadow Copy Provider
If a provider is listed other than the above two, disable and stop the corresponding service.

9. To resolve any VSS-specific errors, please view this article. 

10. For more advanced troubleshooting using VSS trace, please view this article from Microsoft


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