This  information may help you troubleshoot Windows-related Volume Shadow Copy Service (VSS) errors and is intended for informational purposes only.

Note: Because some suggestions are system-related tweaks and registry-setting changes, Axcient cannot assume any responsibility for your system stability. Please use at your own risk.

Symptoms of a Volume Shadow Copy Malfunction

1. Very long (or seemingly indefinite) VSS snapshot generation time with intensive hard drive activity
2. VSS errors reported in the Event Viewer (click start and search Event Viewer in search box to open)
3. VSS errors reported by Microsoft’s Volume Shadow Copy tool vssadmin
4. VSS fails to create snapshots
5. Errors such as “The writer vetoed the shadow copy creation process”

VSS Repair Suggestion #1

Reboot

For some reason, servers that haven’t been rebooted in a while may cause VSS to malfunction. Rebooting resolves the issue in many cases.

VSS Repair Suggestion #2

Open vssadmin from the command line (run cmd as administrator).

Enter vssadmin delete shadows /all to clean up any dead VSS snapshots. Some defect systems accumulate hundreds of VSS snapshots that persist in the system and cause Windows to become unresponsive.

Enter vssadmin list writers and check for errors. If you receive any errors for one VSS writer, you may need to fix that particular VSS writer. It is common to receive writer errors caused by Microsoft’s Virtual Server 2005 VSS writer.

If you see a VSS writer error, try the following:

Restart the services: COM+ System Application Service, Distributed Transaction Coordinator Service, and Volume Shadow Copy Service and also restart the affected VSS writer service, for example Virtual Server 2005 VSS writer or Hyper-V VSS writer.

Check the Event Viewer for any additional error information logged by that VSS writer. Run again vssadmin list writers to check if the above resolved the problem. If it didn’t follow with the next suggestion below:

VSS Repair Suggestion #3

Check if the Volume Shadow Copy service is started, try restarting the service:

• Click ‘Start’, and then click ‘Control Panel’. Click ‘Administrative Tools’, and then double-click the ‘Services’ snap-in.
• Check for ‘Volume Shadow Copy’.

Also, restart the following services on the affected machine: 

• COM+ Event System Service
• COM+ System Application Service
• Remote Procedure Call (PRC) Service
• MS Software Shadow Copy Provider Service

VSS Repair Suggestion #4

Re-register the Volume Shadow Copy Service:

For Windows 2003:

Create and execute a batch file named

FIXVSS03.BAT:

Please note the following:

• You will need to run the batch file as Administrator.
• This is only for Windows 2003 and not for Windows 2008.
• After running the bat file, you will need to reboot the server to bring all of the writers into a stable state.

Copy and paste the following into Notepad, then click Save As, to save it as FIXVSS03.BAT.

rem FILENAME: FIXVSS03.BAT
rem
net stop vss
net stop swprv
cd /d %windir%\system32
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

For Windows 2008:

Create and execute a batch file named

FIXVSS08.BAT:

Please note the following:

• You will need to run the batch file as Administrator.
• This is only for Windows 2008 not for Windows 2003.
• After running the bat file, you will need to reboot the server to bring all of the writers into a stable state.

Copy and paste the following into Notepad, then click Save As, to save it as FIXVSS08.BAT.

rem FILENAME: FIXVSS08.BAT
rem
net stop “System Event Notification Service”
net stop “Background Intelligent Transfer Service”
net stop “COM+ Event System”
net stop “Microsoft Software Shadow Copy Provider”
net stop “Volume Shadow Copy”
cd /d %windir%\system32
net stop vss
net stop swprv
regsvr32 /s ATL.DLL
regsvr32 /s comsvcs.DLL
regsvr32 /s credui.DLL
regsvr32 /s CRYPTNET.DLL
regsvr32 /s CRYPTUI.DLL
regsvr32 /s dhcpqec.DLL
regsvr32 /s dssenh.DLL
regsvr32 /s eapqec.DLL
regsvr32 /s esscli.DLL
regsvr32 /s FastProx.DLL
regsvr32 /s FirewallAPI.DLL
regsvr32 /s kmsvc.DLL
regsvr32 /s lsmproxy.DLL
regsvr32 /s MSCTF.DLL
regsvr32 /s msi.DLL
regsvr32 /s msxml3.DLL
regsvr32 /s ncprov.DLL
regsvr32 /s ole32.DLL
regsvr32 /s OLEACC.DLL
regsvr32 /s OLEAUT32.DLL
regsvr32 /s PROPSYS.DLL
regsvr32 /s QAgent.DLL
regsvr32 /s qagentrt.DLL
regsvr32 /s QUtil.DLL
regsvr32 /s raschap.DLL
regsvr32 /s RASQEC.DLL
regsvr32 /s rastls.DLL
regsvr32 /s repdrvfs.DLL
regsvr32 /s RPCRT4.DLL
regsvr32 /s rsaenh.DLL
regsvr32 /s SHELL32.DLL
regsvr32 /s shsvcs.DLL
regsvr32 /s /i swprv.DLL
regsvr32 /s tschannel.DLL
regsvr32 /s USERENV.DLL
regsvr32 /s vss_ps.DLL
regsvr32 /s wbemcons.DLL
regsvr32 /s wbemcore.DLL
regsvr32 /s wbemess.DLL
regsvr32 /s wbemsvc.DLL
regsvr32 /s WINHTTP.DLL
regsvr32 /s WINTRUST.DLL
regsvr32 /s wmiprvsd.DLL
regsvr32 /s wmisvc.DLL
regsvr32 /s wmiutils.DLL
regsvr32 /s wuaueng.DLL
sfc /SCANFILE=%windir%\system32\catsrv.DLL
sfc /SCANFILE=%windir%\system32\catsrvut.DLL
sfc /SCANFILE=%windir%\system32\CLBCatQ.DLL
net start “COM+ Event System”

Additional Useful Commands:

1. Open the Command (DOS) Prompt with administrator rights and enter: vssadmin list writers to determine all the VSS writers installed on the machine and their status (stable, error, etc).
2. Open the Command (DOS) Prompt with administrator rights and enter: vssadmin delete shadows /all  to clean up any dead VSS snapshots that may be slowing down the machine.

VSS Repair Suggestion #5

On some systems, the command vssadmin delete shadows isn’t available.

In Windows XP, that’s okay because VSS snapshots can’t be persistent on XP (a reboot will get rid off them); however, on Vista you need to delete old shadows using:

vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=300MB

300MB is usually the smallest amount you can specify and will effectively delete any existing VSS snapshots on your system. If you don’t get any VSS writer errors when using vssadmin list writers but the system isn’t able to create a new VSS snapshot (and you have deleted all existing snapshots), then you may have to actually increase the max shadow storage size on your system. Use the previous command with a greater number, such as 10GB:

vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=10GB

Note that it is also possible to allocate shadow copy storage space on a different drive, as along as it’s local:

vssadmin Resize ShadowStorage /For=C: /On=X: /MaxSize=200GB

VSS Repair Suggestion #6

If the PC or server you are using is a virtual machine host, you need to install the latest VMware Tools (for VMware), Virtual Machine Additions (Virtual Server), or Hyper-V Integration Services (for Hyper-V and Windows Server 2008) on each virtual machine. Try updating them if you have them installed already. Outdated integration services can cause various VSS errors.

VSS Repair Strategy #7

Your computer may have a corrupt COM+ subscription information. Open the registry editor (regedit) and navigate to:

HKLM\Software\Microsoft\EventSystem\{26c409cc-ae86-11d1-b616-00805fc79216}

Then delete the Subscriptions key and reboot the machine. A subsequent call in the command prompt should show no more errors: vssadmin list writers. This VSS repair strategy appears to work well when the System Writer is reporting an error. The Event Viewer may be reporting this or a similar error:

Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Name: System Writer Writer Instance ID: {34162f4c-59ff-468e-848d-cb4b3d8dd7dc}

VSS Repair Suggestion #8

Stop or remove any other backup software on your computer. Other products that also utilize VSS writers need to be stopped during the Axcient back up or removed completely.

VSS Repair Suggestion #9

Install the latest Service Packs and Updates through Windows Update.