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VSS Writer Failed / How to Restart and Re-Register VSS Writers


VSS writers can fail for various reasons, such as two or more resources trying to use the writer at the same time.  When you run vssadmin list writers in a command prompt with admin rights, you might see one of the writers in a failed state, as shown below:

vssadmin list writers

Writer name: 'Microsoft Hyper-V VSS Writer'
   Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
   Writer Instance Id: {c35d6ab0-9588-412f-ae7b-cdc37534501f}
   State: [8] Failed
   Last error: Retryable error


It is important to identify if the issue is transient or if the issue is persistent and requires further diagnosis.  The process below will temporarily resolve most VSS errors, however the cause of that failure may repeat unless independently addressed.  

VSS is a native windows component and it if is failing changes usually are required to windows or other environment behaviors in order to permanently resolve.  Understanding which VSS component is impacted is a key step and whether the issue can be simply reset temporarily or remains in a failed state.  

That said, restarting a windows service may resolve the issue temporarily and allow a manual backup to succeed.  The steps below will temporarily reset many VSS issues: 

  1. On the Windows server in question, open a command prompt with administrative rights and run the command
    vssadmin info
    vssadmin list writers
  2. Check the writers that have failed.  
  3. You can use the list below to find the service that corresponds to the VSS Writer in question.  Restarting the corresponding windows services in many cases will resolve the VSS issues.  
  4. Use the vssadmin list writers command again to show if the vss writer is now in a stable state.  Re-attempt your operation and determine if the writer fails again.  
  5. If the vss writer remains in a failed state after restarting the related service, or immediatly fails again when attempting a backup, you should identify the specifics of the VSS error with further troubleshooting by identifying the specific VSS HREF code in windows.  Additional detailed information is contained in the linked articles below the chart.  


VSS Writer Service Name Related Service To Restart
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
(also restarts DFS Replication)
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
WDS VSS Writer WDSServer Windows Deployment Services Server
WIDWriter WIDWriter Windows Internal Database VSS Writer
WINS Jet Writer WINS Windows Internet Name Service (WINS)
WMI Writer Winmgmt Windows Management Instrumentation


This KB covers common VSS error codes and details on potential cause and resolution steps. 

Again VSS is a native windows service.  Backups do not cause these services to fail.  They fail because VSS is not in a healthy state or runs into software conflicts when a backup requests a snapshot from Windows.  Other underlying conditions in windows, software corruption, antivirus software interference, improperly completed OS updates, software installations done without required reboots, multiple backup products installed in the same machine, under-configured windows resources or storage performance bottlenecks, and more can cause this issue.  Identifying the cause of your VSS issue may not be trivial and in some cases requires expert support from Microsoft itself to resolve.  Rarely can a change from a backup vendor alone resolve or work around VSS issues.  The above information however may be useful in troubleshooting which service is impacting the operation.  



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