BA963: Volume Shadow Copy writer state is unstable¶
| Error code | Product | Applies to |
|---|---|---|
| BA963 | BackupAssist | For BackupAssist 14.0.0 or later. |
Description¶
Volume Shadow Copy Writer State is unstable.
Resolution¶
This condition reports that one or more Volume Shadow Copy Service (VSS) writers were in an unstable state around the time of the backup. It is usually caused by a transient problem with a VSS writer or with the underlying operating system components.
It is not purely informational. It is raised only on a backup that ended with errors, and its severity reflects how recent the writer problem was:
- a major warning when a VSS writer was unstable during the current backup;
- a minor warning when the current backup's writers were stable but the previous backup had a writer problem.
If neither the current nor the previous backup had a writer problem, the condition is not shown. Because it can reflect a problem from an earlier run, a one-off warning after a backup that has since succeeded may not need action, but a recurring warning should be investigated.
Try the following before the next scheduled backup:
- Open an elevated command prompt and run "vssadmin list writers". Confirm that every writer reports a state of "Stable" with no last error. If a writer is not stable, restart the Windows service that hosts it, or reboot the server, to return it to a stable state.
- Install the latest Windows updates, then check the health of the system files by running "sfc /scannow" followed by "DISM /Online /Cleanup-Image /RestoreHealth".
If the problem persists, please contact support for assistance - BackupAssist Support page.
| Last updated | Created | Further assistance |
|---|---|---|
| 15th Sep 2026 | 6th Nov 2025 | BackupAssist Support page |