Volume Shadow Copy Service Errors

1/27/2019 Volume Shadow Copy Service Errors

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Volume Shadow Copy Service Errors

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Volume Shadow Copy Service Errors How to find the cause of common VSS errors.

• How-To

ARTICLE NUMBER

SUMMARY How to find the cause of common VSS errors.

ISSUE Windows Client is showing Volume Shadow Copy Service (VSS) errors.

See this KB (https://support.unitrends.com/UnitrendsBackup/s/article/00000381 8)for examples of specific VSS errors.

RESOLUTION In order to fix Volume Shadow Copy Service (VSS) errors in your system, and before you dive into the details, you need to know exactly what causes these errors in your system. If you encounter CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 1/15 1/27/2019 Volume Shadow Copy Service Errors VSS failures for your Windows Client, you’ll need to check the Windows Event Viewer as follows:

The error may look like this:

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 2/15 1/27/2019 Volume Shadow Copy Service Errors

VolSnap entries may look like this:

What you need to do next if you are using Hyper-V, is to check the Hyper-V logs (following section).

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 3/15 1/27/2019 Volume Shadow Copy Service Errors It also helps to run search using your favorite search engine and search for: VOLSNAP 27 or VSS 8193.

You basically use the Event ID and Source in your search to find additional information online on how to fix your particular error.

Most of the time, however, the way to fix the error becomes obvious when reading the error message, see the following Hyper-V example:

Hyper-V Volume Shadow Copy Errors

If you are using Hyper-V, you may find additional Hyper-V VSS error information by navigating further down to:

Applications and Services Logs -> Microsoft -> Windows -> Hyper- V XXXXXXX

You will find about a dozen different Hyper-V logs and more often than not you’ll find the answer to your problem right there.

The following example shows that the virtual machine’s Hyper-V Integration Services are not available or installed:

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 4/15 1/27/2019 Volume Shadow Copy Service Errors

Please collect as much information as possible and export the Event Viewer logs. Contact support for further investigation.

How to Fix Volume Shadow Copy Service: 11 Strategies

Warning: Serious problems may occur if these commands are executed incorrectly. These problems may require redeployment of the appliance, result in a loss of data, and/or cause system downtime. Unitrends cannot guarantee these problems can be solved and customers should proceed at their own risk.

Step #1: The First Thing To Do Before Attempting Fixes

Check Windows Event Viewer logs and several sub-logs; this will save you hours if not days of work!

This is the most crucial step in fixing the problem: dig through the Event Viewer logs. If you haven’t done this before, it’s a great opportunity to approach it now since the Event Viewer system is where Windows logs almost everything. Once you know the exact cause, the fix is usually trivial.

Repair Strategy #1 of 11

Reboot. For some reason, servers that haven’t been rebooted in a while cause VSS to malfunction. As all Microsoft veterans know, you need to reboot regularly as a preventive and cleanup CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 5/15 1/27/2019 Volume Shadow Copy Service Errors measure for your system. Rebooting will eliminate VSS problems caused by transient VSS errors.

Repair Strategy #2 of 11

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

Enter "diskshadow" and then "delete shadows all" or “vssadmin delete shadows /all” on older OSes to clean up any dead / orphaned shadows. Some defect systems accumulate hundreds of VSS snapshots that persist in the system and cause Windows to become unresponsive. WARNING: Do not run this command if the server or workstation is pending a reboot to install Windows updates!

Enter “vssadmin list writers” and check for errors. If you receive errors for one writer, you may need to fix that particular service . It is quite common to receive multiple errors from several related services, such as “VolSnap” and “Disk”.

If you see a VSS error, try the following:

Restart the services:

COM+ System Application Service, Distributed Transaction Coordinator Service, and Volume Shadow Copy Service

*Edit* 7-27-16 ######################################## Check services for any abnormal state.

Example Virtual Disk Service is stuck in a "Stopping" state, the process may need to be manually stopped and restarted.

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 6/15 1/27/2019 Volume Shadow Copy Service Errors ########################################

and also restart the affected service, for example, the Hyper-V VSS writer.

The most important thing to do is to check the Event Viewer for any additional error information logged. Usually each VSS aware service will have its own logs, most likely inside the Event Viewer.

Run again “vssadmin list writers” to check if the above resolved the problem. If it didn’t follow with the next strategy below:

Repair Strategy #3 of 11

Uninstall all backup utilities on your computer, including Windows Backup if it’s installed. You don’t need to uninstall Unitrends Agent because the Agent doesn’t contain or install any VSS drivers; however, we have seen VSS components of other backup solution developers cause system instability and errors.

After all other backup tools have been uninstalled, open the Registry Editor (regedit) as administrator and check the following branch: “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\VSS\Pr oviders”

Underneath that key you should only find Microsoft Software Shadow Copy Provider 1.0 and no other VSS provider (with the exception of Windows Server 2012 and later, where you’ll find several system providers). If you do find another third-party VSS provider registered, it may be a residue registry entry of a previous software installation. You can save the entry by exporting the entire registry to a file (right click and select Export) and then it’s safe to delete the

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 7/15 1/27/2019 Volume Shadow Copy Service Errors entire branch entry underneath HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\VSS\Pro vider.

Then reboot and try again running “vssadmin list writers” to confirm the problem has been resolved.

Note: If you are using specialized attached storage that requires its own VSS provider, you may see a driver reference in the above registry key. Please leave those kinds of entries intact. In addition, on Windows Server 2012 you may find additional system related VSS providers there, which should also remain referenced

. VSS Repair Strategy #4 of 11

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/2008 you need to delete old shadows using: vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=320MB

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

You can choose to allocate a percentage of disk space instead. Microsoft recommends 20%. That command would look like this for the C: drive. vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=20%

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 8/15 1/27/2019 Volume Shadow Copy Service Errors 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

If you receive the following message, check the Volume Shadow Copy service (must be Automatic or Manual) and if VSS capabilities are disabled or broken. the specified volume shadow copy storage association was not found

If VSS is disabled, you can create it by executing this command vssadmin add shadowstorage /for=c: /on=c:

Also check this article discussing the VSS error "Cannot find anymore diff area candidates" for instructions on how to set the diff area using the Windows user interface on Server operating systems. VSS Repair Strategy #5 of 11

You can try to re-register all VSS and COM+ components by running the following commands from the command prompt as administrator:

These instructions for 32-bit AND 64-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 CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 9/15 1/27/2019 Volume Shadow Copy Service Errors regsvr32 msxml3.dll regsvr32 msxml4.dll regsvr32 Vssapi.dll regsvr32 Vssui.dll

net start vss net start swprv

Execute these instructions only on 64-bit systems in addition to the above:

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

VSS Repair Strategy #6 of 11 CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 10/15 1/27/2019 Volume Shadow Copy Service Errors 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 of 11

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 Strategy #8 of 11

Remove or uninstall all backup tools on your computer. Unitrends Agent doesn't need to be removed because it doesn't add a VSS writer to your system. Other products, however, do add a VSS writer which may be causing the problem. You may receive this error:

CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 11/15 1/27/2019 Volume Shadow Copy Service Errors Volume Shadow Copy Service error: A critical component required by the Volume Shadow Copy service is not registered. This might happened if an error occurred during Windows setup or during installation of a Shadow Copy provider. The error returned from CoCreateInstance on class with CLSID {faf53cc4-bd73-4e36-83f1- 2b23f46e513e} and Name VSSEvent is [0x80040154]

Several users reported that after uninstalling Acronis this error message disappeared.

VSS Repair Strategy #9 of 11

Try uninstalling the virtualization tool you're using (Microsoft Virtual Server, Hyper-V, VMware, etc.) one-by-one, then reboot the client. On some machines, this strategy worked when everything else failed.

Once you get VSS working again properly, install the virtualization platform again from scratch and retest VSS.

VSS Repair Strategy #10 of 11

Install the latest Service Packs and Updates through Windows Update.

Check Microsoft's Support (http://support.microsoft.com/) for hot fixes and other updates to repair VSS.

VSS Repair Strategy #11 of 11 (VSS Error Code 800423f3)

If the VSS error code 0x800423f3 is reported, the reason is a corrupt state of WMI (wmiutils.dll). This may happen if a registry cleaner was used or a third-party application was uninstalled incorrectly. What you need to do is re-register wmiutils.dll and then restart the WMI service. CHAT WITH AN EXPERT https://support.unitrends.com/UnitrendsBackup/s/article/000004447 12/15 1/27/2019 Volume Shadow Copy Service Errors In the command prompt, execute the following three lines (note that stopping the WMI service does NOT stop VMs, it only stops the management service):

net stop winmgmt

regsvr32 wmiutils.dll

net start winmgmt

After that you should start up the Hyper-V Management Service again if needed.

Another cause for this error: You may need to update your Hyper-V virtual machine integration services inside of each VM when you come across this error. See http://technet.microsoft.com/en- us/library/dd582376(v=WS.10).aspx (http://technet.microsoft.com/en- us/library/dd582376(v=WS.10).aspx). Check the vmguest.iso date / time you have in your system folder. You may have different versions of the Hyper-V Integration Services CD on your system. There have been bug reports indicating that Hyper-V uses the wrong ISO file when the VM Action menu is used to install the Integration Services. Try attaching the ISO manually and use the latest vmguest.iso in your system folder.

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