Reset VSS Writers

VSS writers are application-specific components for Microsoft's Volume Shadow Copy Service, which ensure the consistency of application data when a shadow copy is created. That's quite useful for creating consistent backups of a system. However, some of these writers go into error states more or less frequently. And Microsoft did not deem it necessary to document how to reset writers without rebooting the entire system (or at least I didn't manage to find that piece of information).

Since this burnt me once too often, I started compiling a list of VSS writers and the services that need to be restarted to reset each of them. Some are rather obvious, others (System Writer for instance) not so much.

VSS Writer	Service Name	Service Display Name
ASR Writer	VSS	Volume Shadow Copy
BITS Writer	BITS	Background Intelligent Transfer Service
COM+ REGDB Writer	VSS	Volume Shadow Copy
DFS Replication service writer	DFSR	DFS Replication
DHCP Jet Writer	DHCPServer	DHCP Server
FRS Writer	NtFrs	File Replication
FSRM writer	srmsvc	File Server Resource Manager
IIS Config Writer	AppHostSvc	Application Host Helper Service
IIS Metabase Writer	IISADMIN	IIS Admin Service
Microsoft Exchange Writer	MSExchangeIS	Microsoft Exchange Information Store
Microsoft Hyper-V VSS Writer	vmms	Hyper-V Virtual Machine Management
NTDS	NTDS	Active Directory Domain Services
OSearch VSS Writer	OSearch	Office SharePoint Server Search
OSearch14 VSS Writer	OSearch14	SharePoint Server Search 14
Registry Writer	VSS	Volume Shadow Copy
Shadow Copy Optimization Writer	VSS	Volume Shadow Copy
SPSearch VSS Writer	SPSearch	Windows SharePoint Services Search
SPSearch4 VSS Writer	SPSearch4	SharePoint Foundation Search V4
SqlServerWriter	SQLWriter	SQL Server VSS Writer
System Writer	CryptSvc	Cryptographic Services
TermServLicensing	TermServLicensing	Remote Desktop Licensing
WINS Jet Writer	WINS	Windows Internet Name Service (WINS)
WMI Writer	Winmgmt	Windows Management Instrumentation

This list is far from complete. It merely contains those writers I already had to deal with and some contributions from fellow administrators.

You can use PowerShell for listing failed writers:

& vssadmin list writers | Select-String -Context 0,4 '^writer name:' | ? {

  $_.Context.PostContext[2].Trim() -ne "state: [1] stable" -or

  $_.Context.PostContext[3].Trim() -ne "last error: no error"

}

or the state of a particular writer:

$name = [Regex]::Escape('writer name')

& vssadmin list writers | Select-String -Context 0,4 "^writer name: .*$name"