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- Overview
- Check Windows Event Viewer for VSS Events
- Check for Failed VSS Writers
- Ensure the VSS Service is Not Disabled
Overview
Macrium Reflect uses a Microsoft service called Volume Shadow Copy Service (VSS) to create disk images and backup files that are in use.
VSS is a copy-on-write driver that intercepts disk writes before they actually happen. The contents of the disk are written to a shadow copy buffer before the write takes place. The disk image, therefore, represents an exact point-in-time and is not affected by disk write activity during image creation. This article contains more information about VSS and why we use it.
When VSS fails, you are unable to create a disk image or back up open files with Macrium Reflect. Macrium Reflect cannot cause VSS to fail. Any failure is caused by other software or system configuration problems and will affect every program that uses VSS. Failures must be located and fixed for disk images and file backups to complete successfully.
This article contains generic troubleshooting steps that are a good first step when troubleshooting VSS errors; articles for specific VSS errors are listed at the end of this article.
Tip: The Macrium Reflect rescue media can be used to take backups and does not require the use of VSS. If an image is required urgently, and the system can be taken offline for the duration of a backup, this may enable the backup to be created successfully.
Viewing VSS Error Messages
When a VSS error occurs, an error message will usually be displayed in Reflect Monitor during the backup and the resultant log file, which indicates the cause of the error:
More detailed information about the error can also be found in the VSS log file that is created by the backup:
Check Windows Event Viewer for VSS Events
Since VSS is a component of Windows, Windows contains its own logging for VSS-related events; these can be viewed in the Windows Event Viewer. To assist with troubleshooting VSS-related errors, Macrium Reflect includes a tool called 'View Windows VSS Events...', which can be used to filter through the noise of Windows Event Viewer and find events that are related to VSS.
This can be opened in the 'Other Tasks' menu within Macrium Reflect:
Read more about this option here.
Run 'Fix VSS Problems'
Macrium Reflect includes a utility called 'Fix VSS Problems'. This is a good first step for troubleshooting VSS errors, as it will run a variety of common troubleshooting steps, including re-registering VSS DLLs, restarting the VSS service, and repairing registry entries.
The 'Fix VSS Problems...' utility can be found in the 'Other Tasks' menu in Macrium Reflect:
After selecting 'Fix VSS Problems...', the following window will be displayed:
Select 'Run' to run 'Fix VSS Problems...'.
Following this, attempt the backup again; if the error persists, follow the additional troubleshooting steps below.
Check for Failed VSS Writers
VSS uses writer components to ensure that the file system is in a stable state when creating your disk image. For example, SQL database writers ensure that all transactions to databases are complete before allowing the shadow copy service to continue. If these writers are in a failed state, it may prevent the VSS snapshot from being created.
Macrium Reflect will automatically attempt to create a VSS snapshot without the use of VSS writers when a VSS snapshot creation fails. This may allow a VSS snapshot to be created and the backup to proceed; you may see a message similar to the example below in the log file:
Failed: Failed - 0x8000ffff - Catastrophic failure - Retrying without VSS Writers
Success
This indicates that the snapshot has been created without VSS writers and may cause VSS-aware applications to be backed up in a "crash consistent" state. It is recommended that you still troubleshoot the VSS writers.
Windows includes a VSS administration program (vssadmin) that can list the status of all VSS Writers you have on your system. To query the status of the writers, open an elevated command prompt and run the following command:
vssadmin list writers
The output will look similar to the example below:
C:\Windows\system32>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.
Writer name: 'Task Scheduler Writer'
Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b}
State: [1] Stable
Last error: No error
Writer name: 'VSS Metadata Store Writer'
Writer Id: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06}
Writer Instance Id: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93}
State: [1] Stable
Last error: No error
Writer name: 'Performance Counters Writer'
Writer Id: {0bada1de-01a9-4625-8278-69e735f39dd2}
Writer Instance Id: {f0086dda-9efc-47c5-8eb6-a944c3d09381}
State: [1] Stable
Last error: No error
Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {7e0b3be5-8a13-4327-a6b8-a47a7be4092d}
State: [1] Stable
Last error: No error
Writer name: 'ASR Writer'
Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
Writer Instance Id: {8cae18ac-26bb-46da-964d-d0d057f8e7d2}
State: [1] Stable
Last error: No error
Writer name: 'Shadow Copy Optimization Writer'
Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
Writer Instance Id: {5ec93b1f-1791-44c6-b242-114ec2233d19}
State: [1] Stable
Last error: No error
Writer name: 'Registry Writer'
Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
Writer Instance Id: {9abb6ce7-cf79-406f-8f95-c123b227bbe1}
State: [1] Stable
Last error: No error
Writer name: 'COM+ REGDB Writer'
Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
Writer Instance Id: {a5069cb5-1959-47d9-820e-08a616f83b48}
State: [1] Stable
Last error: No error
Writer name: 'WMI Writer'
Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
Writer Instance Id: {6019e32c-41d1-4039-a939-f07d22c1cd38}
State: [1] Stable
Last error: No error
Writer name: 'MSSearch Service Writer'
Writer Id: {cd3f2362-8bef-46c7-9181-d62844cdc0b2}
Writer Instance Id: {fc3dbcf8-4ea5-4d6b-89c4-29f63d592266}
State: [1] Stable
Last error: No error
'No error' indicates that the VSS writer is in a healthy state. A 'Failed' state indicates that the VSS writer is in a failed state and may require troubleshooting. 'Last error' will include the last error message that the VSS writer failed with and can be used to assist with troubleshooting:
Writer name: 'SqlServerWriter'
Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
Writer Instance Id: {bcd8fa6e-0e55-45c9-91e3-2ab7c5170e91}
State: [8] Failed
Last error:Unexpected Error
The Windows Event Viewer will likely contain additional information about the cause of the error. The example below shows an extract of Windows Event Viewer that is associated with the error above:
Once 'vssadmin list writers' returns that all of the writers are in a 'No error' state, attempt the backup again.
Ensure the VSS Service is Not Disabled
Changing the 'Startup type' of the Volume Shadow Copy service and rebooting the system often resolves VSS errors during backups. To do this, open 'Run' by pressing the key combination Windows Key + R. In the window that opens, search 'Services.msc':
In Services, find 'Volume Shadow Copy', then right-click and select 'Properties':
In the 'General' tab of 'Properties', use the dropdown menu next to 'Startup type' to select 'Automatic':
Select 'OK', then restart the system. Once the system has restarted, attempt the backup again.
Specific VSS Errors
The above steps are a good starting point for troubleshooting VSS errors. However, additional steps may be required to resolve some VSS errors. The articles linked below contain additional troubleshooting steps for some of the more common VSS errors:
VSS Error: VSS_E_SNAPSHOT_SET_IN_PROGRESS