Resolving VSS Writer Errors in Windows XP, Windows 7, and Windows Server 2003

Topic

This article describes how to resolve VSS Writer errors without rebooting Windows.

Environment

• Windows XP
• Windows 7
• Windows Server 2003

Description

There are three scenarios in which to use these instructions:

• Failed VSS Writers: Backups fail because an agent's VSS writers are in a failed state, but it is impossible or not desirable to restart the server until at least after business hours.
• VSS Writers Not Started: There may also be a writer that is not running and needs to be. Running the command vssadmin list writers will only show a list of writers in a "started" state.
• VShadow is in use for Windows Server 2003 or XP: VSS is available in the Volume Shadow Copy Service 7.2 SDK, which you can download from the Windows Download Center.

Troubleshooting

Failed VSS writers

Find the failed VSS writers and their associated services, and restart them:

1. Click the Start button then type CMD. When the command prompt icon appears, right-click it and select Run as Administrator.
2. Type vssadmin list writers to find each of the VSS writers in a failed state. If the command hangs and does not return any output, this suggests the Volume Shadow Copy service or one of its dependent tasks might be in a bad state, causing the VSS writer audit to fail.

Figure 1: Admin command prompt

3. Restart the service to clear the failed state. If the service will not restart, reboot the production machine.
4. Make a list or take a screenshot of all failed VSS writers.
5. Find the VSS writer's associated Service Display Name in the table below and restart the service.

Figure 2: Failed VSS Writer

6. Open services.msc and stop any VSS related services that are running.
7. Re-run the command vssadmin list writers in an administrative command prompt to confirm the state has changed to Stable with no errors.

Figure 3: Stable VSS writer

8. Try another backup. If the VSS writers fail again, you must reboot the machine.

VSS Writer	Service Name	Service Display Name
ADAM $instanceName Writer	ADAM_$instanceName	$instanceName
ASR Writer	VSS	Volume Shadow Copy
BITS Writer	BITS	Background Intelligent Transfer Service
Certificate Authority	CertSvc	Active Directory Certificate Services
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 Replica Writer	MSExchangeRepl	Microsoft Exchange Replication Service
Microsoft Exchange Writer	MSExchangeIS	Microsoft Exchange Information Store
Microsoft Hyper-V VSS Writer	vmms	Hyper-V Virtual Machine Management
MSMQ Writer (MSMQ)	MSMQ	Message Queuing
MSSearch Service Writer	WSearch	Windows Search
NPS VSS Writer	EventSystem	COM+ Event System
NTDS	NTDS	Active Directory Domain Services
OSearch VSS Writer	OSearch	Office SharePoint Server Search
OSearch14 VSS Writer	OSearch14	SharePoint Server Search 14
OSearch15 VSS Writer	OSearch15	SharePoint Server Search 15
Registry Writer	VSS	Volume Shadow Copy
Shadow Copy Optimization Writer	VSS	Volume Shadow Copy
SharePoint Services Writer	SPWriter	Windows SharePoint Services VSS Writer
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
System Writer	CryptSvc	Cryptographic Services
TermServLicensing	TermServLicensing	Remote Desktop Licensing
WDS VSS Writer	WDSServer	Windows Deployment Services Server
WIDWriter	WIDWriter	Windows Internal Database VSS Writer
WINS Jet Writer	WINS	Windows Internet Name Service (WINS)
Windows Server Storage VSS Writer	WseStorageSvc	Windows Server Essentials Storage Service
WMI Writer	Winmgmt	Windows Management Instrumentation

VSS Writer Not Started

1. In the Datto device UI, Click Configure Agent Settings for the machine that is failing backups, then select VSS Writer Exclusion from the left-hand menu.

Figure 4: VSS Writer Exclusion

2. Click the Start button then type CMD. When the command prompt icon appears, right-click it and select Run as Administrator.
3. Run the command vssadmin list writers
4. Compare the output of the command to the VSS Writer Exclusion list in the Datto device UI. If there are some missing in the command prompt output, find the associated service in the table above and make sure it is started.
5. Re-run vssadmin list writers in the same command prompt. Verify the list of writers matches with the list of writers viewed under VSS Writer Exclusion.

Windows Server 2003 or XP

1. Open services.msc and stop any VSS-related service that is currently running, including:
   • Background Intelligent Transfer Service
   • MS Software Shadow Copy Provider
   • Microsoft Software Shadow Copy Provider
   • Volume Shadow Copy
   • SQL Server VSS Writer
   • Windows Backup
   • Hyper-V Volume Shadow Copy Requester

2. Download Volume Shadow Copy Service SDK 7.2 (external link).
3. Save the vshadow.exe program to the path of %windir%\system32\

Figure 5: Volume Shadow Copy Service SDK 7.2 installation screen

4. Open an administrative command prompt and run the vshadow [volume] command for all volumes. Volume letters should match those of the system's volume/disk drive letters.

Figure 5: The vshadow command

5. Run the vssadmin list writers command to confirm that the VSS writers are now in a stable and ready state (see Figure 1 above).
6. Retry a backup. If the backup fails with VSS writers, reboot the machine, or follow the steps for VSS Writers Not Started above.

NOTE  If following these steps does not repair the writers, even after a full reboot of the production machine, you will need to contact Microsoft, or review their articles in the Troubleshooting VSS Applications(external link) section of their Knowledge Base. Datto is unable to provide extended support for VSS writers, as they are a proprietary Windows application.