VSS Writer Failed: Re-registering VSS Writers on Windows Server

Most backup solutions for Windows use Volume Shadow Copy Service (VSS) to create backup copies of the application or service data. In some cases, the VSS service or one of its writers start to work incorrectly which results in failures during the backup. I have faced such an problem on Exchange, MSSQL and Hyper-V servers. To quickly recover VSS and its components, I use the following instruction.

To detect a failed VSS writer, let’s display the list of VSS writers registered in the system and their status using the vssadmin command.
vssadmin list writers

Find the components with the Failed state in the list. For the components working normally, the state looks as follows: State: [1] Stable.

Writer name: 'Microsoft Exchange Writer'
Writer Id: {53da1ac4-4bab-404a-0917-ae23f8aacfb7}
Writer Instance Id: {61b56ab0-9588-432f-ae7b-3233753ffa38}
State: [7] Failed
Last error: Retryable error

As you can see, in our case Microsoft Exchange Writer has failed (State: [8] Failed), so you won’t be able to complete the Exchange backup. Typically, to fix the state of this component, it’s enough to restart the server (which is not always possible for production reasons).

To repair the Exchange writer, try to restart the related service. (The table below shows the list of typical VSS Writers and the related Windows services.) Besides stopping the service, sometimes you will have to kill a hung service process manually.

VSS Writer	System Service Name	Full Name of a Service
IIS Config Writer	AppHostSvc	Application Host Helper Service
BITS Writer	BITS	Background Intelligent Transfer Service
Certificate Authority	CertSvc	Active Directory Certificate Services
System Writer	CryptSvc	Cryptographic Services
DFS Replication service writer	DFSR	DFS Replication
DHCP Jet Writer	DHCPServer	DHCP Server
NPS VSS Writer	EventSystem	COM+ Event System
IIS Metabase Writer	IISADMIN	IIS Admin Service
Microsoft Exchange Writer	MSExchangeIS	Microsoft Exchange Information Store
Microsoft Exchange Replica Writer	MSExchangeRepl	Microsoft Exchange Replication Service
MSMQ Writer (MSMQ)	MSMQ	Message Queuing
NTDS	NTDS	Active Directory Domain Services
FRS Writer	NtFrs	File Replication
OSearch VSS Writer	OSearch	Office SharePoint Server Search
OSearch14 VSS Writer	OSearch14	SharePoint Server Search 14
SMS Writer	SMS_SITE_VSS_WRITER	SMS_SITE_VSS_WRITER
SPSearch VSS Writer	SPSearch	Windows SharePoint Services Search
SPSearch4 VSS Writer	SPSearch4	SharePoint Foundation Search V4
SqlServerWriter	SQLWriter	SQL Server VSS Writer
FSRM writer	srmsvc	File Server Resource Manager
TermServLicensing	TermServLicensing	Remote Desktop Licensing
Microsoft Hyper-V VSS Writer	vmms	Hyper-V Virtual Machine Management
ASR Writer	VSS	Volume Shadow Copy
COM+ REGDB Writer	VSS	Volume Shadow Copy
Registry Writer	VSS	Volume Shadow Copy
Shadow Copy Optimization Writer	VSS	Volume Shadow Copy
WDS VSS Writer	WDSServer	Windows Deployment Services Server
WIDWriter	WIDWriter	Windows Internal Database VSS Writer
WMI Writer	Winmgmt	Windows Management Instrumentation
WINS Jet Writer	WINS	Windows Internet Name Service (WINS)
MSSearch Service Writer	WSearch	Windows Search

Run the following command again:

vssadmin list writers

Check the status of the problem VSS writer. If it hasn’t changed to Stable state and the problem is not fixed, you can try to re-register the VSS components and libraries.

Go to this directory:

cd c:\windows\system32

Stop the following services: Volume Shadow Copy and Microsoft Software Shadow Copy Provider.

Net Stop VSS
Net Stop SWPRV

Re-register the VSS components:

regsvr32 /s ole32.dll
regsvr32 /s oleaut32.dll
regsvr32 /s vss_ps.dll
vssvc /register
regsvr32 /s /i swprv.dll
regsvr32 /s /i eventcls.dll
regsvr32 /s es.dll
regsvr32 /s stdprov.dll
regsvr32 /s vssui.dll
regsvr32 /s msxml.dll
regsvr32 /s msxml3.dll
regsvr32 /s msxml4.dll
vssvc /register

Start the previously stopped services:
Net Start SWPRV
Net Start VSS

Make sure that the error of the problem VSS writer has disappeared.

This method of restarting and re-registering of VSS components is effective both on Windows Server 2008 / 2012/ R2 and on Windows Server 2016.