The Volume Shadow Copy Service or VSS, a Microsoft product that is included in Windows, is used to back up MS Exchange, MS SQL, MS SharePoint, system states and Hyper-V data. VSS errors that present in the backup client can be seen in the Windows application event logs, such as:
Backup failed to complete: Could not add volume '\\?\Volume{389776ff-0dc1-11e4-93e8-806e6f6e6963}\' to VSS snapshot (0x8004230f; unexpected provider error)
(when a backup is initiated while a second VSS writer is already running).
How to address this
1. The first step in dealing with a VSS error is to run the command-line 'vssadmin list writers'. Depending on the Windows roles and products installed, the number of writers that is displayed will vary. In a healthy system, all reports should read as ‘[1] Stable’ with ‘No error’, as seen below.
2. If any of the writers reports as anything other than '[1] Stable', you need to restart the VSS service. The list below shows which service you need to restart based on which VSS writer has failed.
| VSS Writer | Process (.exe) | Service |
| 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 |
| FRSM 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 | Message Queuing |
| MSSearch Service Writer | WSearch | Windows Search |
| NTDS | NTDS | Active Directory Domain Services |
| O_Search VSS Writer | OSearch | Office SharePoint Server Search |
| O_Search 14 VSS Writer | OSearch14 | SharePoint Server Search 14 |
| Registry Writer | VSS | Volume Shadow Copy |
| Shadow Copy Optimization Writer | VSS | Volume Shadow Copy |
| SMS Writer | SMSSITEVSSWRITER | 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 |
| WIDWriter | WIDWriter | Windows Internal Database VSS Writer |
| WINS Jet Writer | WINS | Windows Internet Name Service (WINS) |
| WMI Writer | Winmgmt | Windows Management Instrumentation |
3. After restarting the service, run the 'vssadmin' command again to check whether the relevant writer is still in a failed state. If there is no improvement, a full reboot of the server is required.
4. If the issue persists, check the event logs from around the time of the error and check the VSS service for errors. Please check these against Microsoft's lists of VSS events.
5. If you need any assistance, please log a ticket containing:
- the Windows Application and System Event Logs in .evtx format
- the device name
- the output file of the following commands:
- vssadmin list writers >C:\writers.txt
- vssadmin list providers >C:\providers.txt
- vssadmin list shadows >C:\shadows.txt
- vssadmin list shadowstorage >C:\shadowstorage.txt
- the number of disks that you have, plus the free disk space on each
Comments
0 comments
Article is closed for comments.