📝 ​Disclaimer
The steps outlined in this article should be carried out only after consulting your System Administrator. As VSS is an operating system component, it is recommended to consult Microsoft or your System Administrator before proceeding.

Volume Shadow Copy Service (VSS) is a Windows component that Druva uses to create consistent snapshots of files — including open or in-use files — during backup. If VSS fails, the Druva backup may fail or fall back to backing up the actual volume directly.

This article provides solutions for the most common VSS error codes encountered during Druva backup and restore operations on Windows endpoints.

Run these commands first. They cover the most common root causes and resolve many VSS issues before digging into specific error codes.

vssadmin list writers

All writers should report State: [1] Stable with no errors or warnings. A failed or timed-out writer is often the root cause of backup failures.

vssadmin list providers

You should see only the Microsoft Software Shadow Copy provider. If third-party providers are listed, they may be interfering with backup snapshot creation.

Open Services by running services.msc. Confirm the following:

Open Event Viewer (eventvwr.msc) and check the Application and System logs. Filter by Source: VSS to find detailed error messages around the time of the backup failure.

Several errors below require re-registering VSS system DLLs. Run the following commands from an elevated Command Prompt (Run as Administrator):

cd /d %windir%\system32

net stop vss

net stop swprv

regsvr32 ole32.dll

regsvr32 oleaut32.dll

regsvr32 vss_ps.dll

vssvc /register

regsvr32 /i swprv.dll

regsvr32 /i eventcls.dll

regsvr32 es.dll

regsvr32 stdprov.dll

regsvr32 vssui.dll

regsvr32 msxml.dll

regsvr32 msxml3.dll

regsvr32 msxml4.dll

net start vss

📝Note

The last command (net start vss) may not succeed if the VSS service is set to Manual start. This is expected. Trigger a backup to verify the issue is resolved.

Druva backup fails because VSS cannot create a snapshot. The client log shows: 0x8000ffff [Catastrophic failure]. Continuing with actual volume...

• The COM+ Event System service is not running.

• The Volume Shadow Copy service is not running.

1. Press Win + R, type services.msc, and press Enter.

2. Locate COM+ Event System. Set Startup Type to Automatic and ensure the service is Running.

3. Locate Volume Shadow Copy. Set Startup Type to Manual and start the service.

4. Retry the Druva backup.

Druva backup fails because VSS cannot find a registered provider. The client log shows: 0x80042304: The volume shadow copy provider is not registered in the system.

VSS DLL files are corrupted or unregistered.

Re-register VSS DLLs — see the Re-registering VSS DLLs section above.

A VSS provider is blocking snapshot creation. Druva backup fails. This may be caused by a third-party VSS provider conflict, corrupted DLLs, or a non-NTFS destination volume.

vssadmin list providers

If you see providers other than Microsoft Software Shadow Copy provider 1.0, consider uninstalling them — third-party providers are a common cause of this error. If the command hangs, a newly installed VSS provider is likely malfunctioning; uninstall it.

Ensure Druva backup is not running at the same time as another backup tool. Some providers allow only one snapshot at a time.

Run CHKDSK on the affected volume:

chkdsk C: /f

If Windows is in a setup or upgrade state, VSS may be blocked. Open Registry Editor (regedit) and navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\Setup

Ensure SystemSetupInProgress and UpgradeInProgress are both set to 0.

Re-register VSS DLLs — see the Re-registering VSS DLLs section above.

VSS requires the destination drive to be formatted as NTFS. Confirm in File Explorer or Disk Management.

Druva backup is having difficulty backing up open or in-use files. VSS cannot locate the required snapshot object.

A VSS component (service or writer) that the backup depends on is unavailable or has not been properly registered.

5. Open an elevated Command Prompt (Run as Administrator) and run:

net stop vss

net stop swprv

6. Re-register VSS DLLs — see the Re-registering VSS DLLs section above.

7. Reboot the machine.

8. After reboot, run vssadmin list writers and confirm all writers show State: [1] Stable with no errors.

9. Retry the Druva backup.

Druva backup fails because VSS cannot shadow copy the specified volume. This is commonly seen on cluster shared volumes or when required VSS services are disabled.

The Microsoft Software Shadow Copy Provider service or the Volume Shadow Copy service is disabled or not starting correctly.

10. Press Win + R, type services.msc, and press Enter.

11. Locate Microsoft Software Shadow Copy Provider. Set Startup Type to Manual and click Start.

12. Locate Volume Shadow Copy. Set Startup Type to Manual and click Start.

13. Reboot the machine and retry the Druva backup.

Windows has a hard limit of 64 shadow copies per volume. When this limit is reached, new shadow copies cannot be created and Druva backup fails.

The volume has accumulated 64 shadow copies. Older copies are automatically deleted when the limit is reached, but VSS still returns an error when attempting to create a new copy at the limit.

vssadmin list shadows

vssadmin delete shadows /For=C: /Oldest

Confirm the deletion when prompted. Repeat if necessary until backup succeeds.

If the error persists, delete all shadow copies for the volume:

vssadmin delete shadows /For=C: /All /Quiet

VSS could not flush data to the volume in time to create the snapshot. Druva backup fails or falls back to live-volume backup.

High disk I/O activity prevents VSS from completing the snapshot within the default time window.

14. Verify the VSS service is running: press Win + R, type services.msc, and confirm Volume Shadow Copy is started.

15. Schedule Druva backups during off-peak hours when disk activity is low (e.g., nights or weekends).

16. Check disk health and repair fragmentation: chkdsk C: /f /r

17. After CHKDSK, run vssadmin list writers to confirm all writers are in State: [1] Stable.

18. If the error persists, contact Druva Support — the VSS timeout threshold may need to be adjusted via registry.

VSS encountered a problem while sending events to writers. This is typically a transient I/O issue — the system was unable to hold I/O writes during the snapshot window.

19. Wait 10 minutes and retry the Druva backup.

20. If the error recurs, check Event Viewer (eventvwr.msc) > Application and System logs, filtered by Source: VSS, for additional context.

21. If the error persists across multiple backup attempts, investigate disk health using chkdsk and review disk I/O load during backup windows.

Druva backup fails because VSS cannot communicate with one or more writers. This may indicate the VSS service has stopped, or a specific writer (e.g., SQL Writer, Registry Writer, System Writer) has failed.

The VSS service or a VSS writer is not running or has encountered an error. This can also occur when the VSS writer infrastructure is not initialized correctly.

22. Run vssadmin list writers to identify any writers showing a failed or timed-out state.

23. Restart the VSS service from an elevated Command Prompt:

net stop vss

net start vss

24. If a specific writer is in a failed state (e.g., SQL Server VSS Writer), restart the Windows service associated with that writer.

25. Check Event Viewer for VSS-related errors in the Application and System logs around the time of the failure.

26. Retry the Druva backup.

VSS is already running — either from a concurrent backup job or a previous VSS process that did not terminate properly. Druva cannot start a new snapshot.

• More than one backup tool is running simultaneously.

• A previous VSS snapshot process stalled and is still active.

27. If multiple backup applications are installed, disable all except Druva and retry.

28. List and clear stale shadow copies from an elevated Command Prompt:

vssadmin list shadows

vssadmin delete shadows /All /Quiet

29. Restart the VSS service:

net stop vss

net start vss

30. If the issue persists, reboot the machine — this reliably clears stuck VSS processes.

31. Re-register VSS DLLs — see the Re-registering VSS DLLs section above.

A VSS writer failed to respond during snapshot creation. The writer may have crashed or become unresponsive. This is more common on systems with high disk activity or heavily fragmented volumes.

32. Run vssadmin list writers and identify which writer is failing.

33. Restart the Windows service associated with the failing writer.

34. Run disk defragmentation on the affected volume to reduce I/O latency.

35. Reduce concurrent disk activity during the Druva backup window.

36. Retry the Druva backup.

VSS encountered an unexpected error while processing the backup operation. The client log may show: The shadow copy provider had an unexpected error while trying to process the specified operation.

VSS system files are not registered, or the Microsoft Software Shadow Copy Provider service is not running.

37. Press Win + R, type services.msc, and press Enter.

38. Locate Microsoft Software Shadow Copy Provider. Set Startup Type to Manual and start the service.

39. If step 2 does not resolve the issue, re-register VSS DLLs:

Re-register VSS DLLs — see the Re-registering VSS DLLs section above.

VSS returned a bad state error, typically when a snapshot is requested that includes remote components but no local components. Druva backup fails to create a snapshot.

The backup components object is not initialized correctly, or the VSS API was called out of sequence.

40. Ensure Windows is fully up to date — this issue has been addressed in Windows Updates.

41. Retry the Druva backup after applying updates.

42. If the problem persists, contact Druva Support with the Druva client logs from: %ProgramData%\Druva\logs

VSS writers timed out during a lengthy shadow copy creation, causing the revert to fail and the volume to be lost from the snapshot set.

This typically occurs on computers with slow hard disks, low memory, or disabled disk write cache, where VSS writers cannot complete operations within the timeout window.

43. Ensure all current Windows Updates are installed.

44. Review hardware performance: check disk speed, available memory, and whether disk write cache is enabled.

45. If the problem persists, contact Druva Support with the Druva client logs.

VSS attempted to import transportable hardware snapshots but some failed because the import did not complete within the timeout window.

VSS timed out waiting for logical unit numbers (LUNs) to come online — this can happen when hardware arrays are approaching the 64-shadow-copy limit.

46. Ensure all current Windows Updates are installed.

47. Delete older shadow copies to reduce the count on affected volumes (see Errors 0x80042312 and 0x80042317 above).

48. If the problem persists, contact Druva Support.

The VSS import operation failed completely. No shadow copies were successfully imported.

The affected volume spans multiple partitions or disks. VSS only marks the first partition; additional partitions are not flagged, so VSS cannot import shadow copies for them.

49. Ensure all current Windows Updates are installed — this is a known VSS issue addressed in Windows patches.

50. If the problem persists, contact Druva Support with the Druva client logs.

The remote machine sharing the volume runs an older version of VSS that does not support remote shadow copy creation.

Ensure the remote machine is running a supported version of Windows with all current updates applied. If the error persists, contact Druva Support.

A volume revert operation is currently running. Only one revert can run at a time.

Wait for the current revert to complete, then retry the Druva backup. If the revert appears stuck, restart the VSS service and reboot the machine.

The active VSS provider does not support shadow copying the specified volume. This is typically a configuration or compatibility issue.

51. Run vssadmin list providers and check for third-party providers.

52. If a non-Microsoft provider is listed, consider removing it to force VSS to use the Microsoft Software Shadow Copy provider.

53. Contact Druva Support if the error persists after removing third-party providers.

A duplicate VSS component with the same logical path and component name already exists. VSS cannot proceed.

54. Restart the VSS service:

net stop vss

net start vss

55. If the issue persists, reboot the machine to clear stale VSS state.

56. Contact Druva Support if the error continues after reboot.

When Druva starts a backup, it creates a VSS snapshot of the backup folders. If snapshot creation fails with this error, the backup fails. The error indicates a third-party VSS provider is registered in the system but its COM class is missing or broken.

A third-party shadow copy provider is registered in Windows but is not functioning correctly. This is often caused by uninstalling software that installed a VSS provider without properly cleaning up the registration.

[YYYY-MM-DD HH:MM:SS] [INFO] Windows VSS failed to create a snapshot for C:\ at step 5,

status 0x8004230f [The shadow copy provider had an unexpected error].

Volume Shadow Copy Service error: Error creating shadow copy provider COM class on

CLSID {3e02620c-...} [0x80040154, class not registered].

Provider ID: {74600e39-...} Class ID: {3e02620c-...}

vssadmin list providers

If you see more than one provider, a third-party provider is present. Note the Provider ID shown in the Event Log.

57. Press Win + R, type regedit, and press Enter.

58. Navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore

59. Right-click the key, select New > DWORD (32-bit) Value, and name it UseMicrosoftProvider.

60. Double-click UseMicrosoftProvider and set the value to 1.

61. Click OK and close Registry Editor.

62. Reboot the machine.

63. Trigger a Druva backup and confirm it completes successfully.

64. Once backup is confirmed working, uninstall the third-party software whose VSS provider was causing the conflict.

Druva uses VSS to create consistent snapshots of files during backup. VSS errors typically indicate that a required Windows service is not running, VSS DLL files are corrupted or unregistered, a third-party VSS provider is conflicting, or the volume has hit the 64 shadow copy limit. Start with the Quick Diagnostics section above.

Open an elevated Command Prompt and run: vssadmin list writers — all writers should show State: [1] Stable with no errors.

See the Re-registering VSS DLLs section in this article for the full command sequence.

Windows supports a maximum of 64 shadow copies per volume. When this limit is reached, new shadow copies cannot be created. Delete the oldest shadow copies using vssadmin delete shadows /For=C: /Oldest to free up capacity.

See Error 0x80040154 above for registry steps to set UseMicrosoftProvider = 1.

Contact Druva Support and provide: the exact error code, the Druva client logs from %ProgramData%\Druva\logs, and the relevant Windows Event Viewer entries (Application and System logs, filtered by Source: VSS).