VSS Basic Troubleshooting Guide
This article applies to:
- OS: All windows OS post WS 2003
- Product edition: inSync Cloud/On-Premise/Phoenix
Overview
This article provides the basic steps to resolve VSS issues before you address error messages or resort to advanced troubleshooting.
Troubleshooting steps
- Check Windows event logs:
Check both the application and system event logs for detailed VSS errors. Subsequently, also check the Hyper-V VMMS events.
- Check third-party backup software:
Check for any third-party backup software. If found, uninstall it and reboot the server. - Check Shadow Storage Space:
Check the storage on each server with the below command.
vssadmin list shadowstorage {/for=<ForVolumeSpec> | /on=<onVolumeSpec>}
Reference: vssadmin list shadowstorage
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
- Check Writers StatusVSS 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
The output must include all the writers listed and must be in a stable state.
- Troubleshoot unstable/failed writers using the common steps:
- Check the service account of the corresponding writer. Ensure it is a system account.
- Check the event log.
- Check the service of the corresponding writer. List of some corresponding services mentioned below:
- Hyper-V Virtual Machine Management
- SQL Server VSS Writer
- Oracle VSS writer
- System Writer
- Restart the concerned service and run the above command again.
- 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
- Re-register all VSS & COM+ components.
Run the following command using elevated command prompt.
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
- Multiple Providers
- At the elevated command prompt, run the following command
vssadmin list providers
-
The output must list one or maximum two providers as follows:
-
'Microsoft Software Shadow Copy provider 1.0
-
Microsoft File Share Shadow Copy Provider
-
- If there is any provider other than the above two, disable and stop the services corresponding to these providers. For example, the following providers.
- Acronis VSS HW Provider
- StorageCraft Volume Snapshot Software Provider
- At the elevated command prompt, run the following command
- To resolve any VSS-specific errors, use the solutions provided in the Troubleshooting VSS errors section.
- For advanced troubleshooting such as VSS trace, refer the Microsoft blogs: How VSS Tracing Works and Using Tracing Tools with VSS.