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How to resolve VSS writer errors without rebooting (VShadow)

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Background

This article describes how to resolve VSS Writer errors without rebooting Windows. Here are the scenarios in which you'd want to use these instructions:

Scenario 1: Failed VSS Writers

  • There are instances when backups are failing due to an agent's VSS writers being in a failed state, but it is impossible or not desirable to restart the server until at least after business hours.

Scenario 2: 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 that are currently started

Scenario 3: Using VShadow 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

Troubleshooting Scenario 1: Failed VSS writers

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

  1. Run Command Prompt as Administrator (Start > Command Prompt > right click on Command Prompt and Run as Administrator)
  2. Find each of the VSS writers in a failed state by issuing this command - vssadmin list writers.


    Figure 1

  3. If the vssadmin list writers command hangs and does not return any output, this is an indication that the Volume Shadow Copy service itself, or one of its dependent tasks, might be in a bad state, causing the VSS writer audit to fail. Restarting this service will typically clear this state. If the service will not restart, a reboot of the production machine is likely required.
  4. Make a list of all the failed VSS writers or take a screenshot.
  5. Find the VSS writer's associated Service Display Name in the table below and restart the service (helpful table below).


    Figure 2

  6. Open services.msc (Start > Runservices.msc), and stop any VSS related service that are running.
  7. Run the command vssadmin list writers again in elevated command prompt to confirm the status has changed to Stable with No Error.


    Figure 3

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

VSS Writers and Corresponding Service Table

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)
WMI Writer Winmgmt Windows Management Instrumentation

Troubleshooting Scenario 2: VSS Writer Not Started

  1. Go to the Datto Remote Web. Click on Configure Agent Settings (for the machine that is failing backups) > VSS Writer


    Figure 4

  2. Run an elevated Command Prompt on your target system (Start > Command Prompt (right click, Run as administrator).
  3. Run the command vssadmin list writers
  4. Compare the output of the command to the list of VSS writers in the VSS Writer Exclusion list in the Remote Web of the Datto. If there are some missing in the list of writers in the command prompt, find the associated service, and make sure it is started or restart it.
  5. Run vssadmin list writers again in the same command prompt. Verify the list of writers match with the list of writers viewed under VSS Writer Exclusion.

Troubleshooting Scenario 3: Windows Server 2003 or XP

  1. Open services.msc (Start > Run > services.msc) and stop any VSS related service that is currently running. This includes:
    • 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
  1. Download Volume Shadow Copy Service SDK 7.2: http://go.microsoft.com/fwlink/p/?linkid=84081
  2. Save the vshadow.exe program to the path of %windir%\system32\


    Figure 5

    Note: This will allow you to run the vshadow command from all directories of the system via the command prompt in step 4.
  1. Open Command Prompt as Administrator and run the command, for example: vshadow C:


    Figure 6

    Note: Volume letter(s) should match those of the system's volume/disk drive letters.
  2. Run the vssadmin list writers command to confirm that the VSS writers are now in a stable and ready state. (see Figure 1 above)
  3. Retry a backup.
  4. If the backup fails with VSS writers you may need to reboot, or follow the steps in Scenario 2.

More information on how ShadowProtect and VSS interact can be found here: https://www.storagecraft.com/support/kb/article/245

 


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