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 writerswill 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 Scenario 1: Failed VSS writers
Find the failed VSS writers and their associated services, and restart them:
- Run Command Prompt as Administrator (Start > Command Prompt > right click on Command Prompt and Run as Administrator)
- Find each of the VSS writers in a failed state by issuing this command -
vssadmin list writers.
- If the
vssadmin list writerscommand 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.
- Make a list of all the failed VSS writers or take a screenshot.
- Find the VSS writer's associated Service Display Name in the table below and restart the service (helpful table below).
- Open services.msc (Start > Run > services.msc), and stop any VSS related service that are running.
- Run the command
vssadmin list writersagain in elevated command prompt to confirm the status has changed to Stable with No Error.
- Try another backup
- 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|
|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
- Go to the Datto Remote Web. Click on Configure Agent Settings (for the machine that is failing backups) > VSS Writer
- Run an elevated Command Prompt on your target system (Start > Command Prompt (right click, Run as administrator).
- Run the command
vssadmin list writers
- 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.
vssadmin list writersagain 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
- 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
- Download Volume Shadow Copy Service SDK 7.2: http://go.microsoft.com/fwlink/p/?linkid=84081
- Save the vshadow.exe program to the path of %windir%\system32\
Note: This will allow you to run the vshadow command from all directories of the system via the command prompt in step 4.
- Open Command Prompt as Administrator and run the command, for example:
Note: Volume letter(s) should match those of the system's volume/disk drive letters.
- Run the
vssadmin list writerscommand to confirm that the VSS writers are now in a stable and ready state. (see Figure 1 above)
- Retry a backup.
- 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