Acronis VSS Doctor: Quick Guide to Fixing Volume Shadow Copy IssuesVolume Shadow Copy Service (VSS) is a Windows technology that creates consistent snapshots of files and volumes so backups, system restores, and other maintenance tasks can run without blocking users or applications. When VSS fails, backups may fail or produce inconsistent results. Acronis VSS Doctor is a specialized tool designed to diagnose and repair many common VSS-related problems. This guide explains what VSS problems look like, how Acronis VSS Doctor works, step-by-step diagnostics and repair procedures, and best practices to prevent future issues.
What is Acronis VSS Doctor?
Acronis VSS Doctor is a troubleshooting utility included with some Acronis backup products. It targets issues with the Microsoft Volume Shadow Copy Service and related components (VSS writers, providers, and the VSS components such as vssvc.exe). It automates many diagnostic steps, can attempt repairs, and produces logs that help administrators understand failures.
Common symptoms of VSS problems
- Backups fail with VSS-related error codes (e.g., 0x80042306, 0x80042308).
- Errors referencing VSS writers or providers in backup logs.
- “Shadow Copy” or “Create Shadow Copy” operations hang or time out.
- System or application restores fail or report inconsistent data.
- Event Viewer contains VSS errors or warnings (Source: VSS, volsnap, or Application/Errors).
How VSS works (brief)
VSS coordinates between three main components:
- VSS Writers — applications (e.g., SQL Server, Exchange) that prepare data for snapshots.
- VSS Providers — software or hardware that actually creates the snapshot (Microsoft provides a default provider).
- VSS Service (vssvc.exe) — orchestrates the snapshot process and mediates between writers and providers.
Problems arise when writers are in a bad state, providers fail, registry/configuration is corrupt, or system resources are insufficient.
Before you begin — prerequisites and precautions
- Run the tool with administrative privileges.
- Ensure you have a recent full backup before performing repairs that affect system components.
- If working on production servers (especially databases), schedule maintenance windows.
- Collect logs: Acronis logs, Windows Event Viewer entries, and any application logs (SQL, Exchange).
Step-by-step: Using Acronis VSS Doctor
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Obtain and run the tool
- Launch Acronis VSS Doctor as administrator from the Acronis installation or support utilities. If not installed, use the version bundled with your Acronis product or download the official support utility from Acronis.
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Let the tool perform diagnostics
- The utility scans VSS service status, enumerates VSS writers and providers, checks related services (COM+ Event System, RPC), and reviews registry keys and permissions.
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Review diagnostic output
- Look for writers with states other than Stable (commonly Waiting for completion, Retryable, Failed) and any providers missing or failing.
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Attempt automated repairs
- Acronis VSS Doctor can attempt to restart services, re-register VSS components, reset writer states, and fix common permissions/registry issues. Allow these actions when safe.
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Manual follow-ups if automated fix fails
- Restart VSS-related services: Volume Shadow Copy, Microsoft Software Shadow Copy Provider, COM+ Event System, RPC.
- Re-register VSS DLLs and COM components (see list below).
- Check disk space on system and shadow storage; reduce shadow storage usage or resize if full.
- Inspect Event Viewer for underlying application errors (e.g., SQL writer errors) and address them.
Common manual repairs (commands)
Run Command Prompt as Administrator. Example common re-registration commands:
net stop vss net stop swprv regsvr32 /s ole32.dll regsvr32 /s vss_ps.dll regsvr32 /s swprv.dll regsvr32 /s comsvcs.dll regsvr32 /s msxml3.dll regsvr32 /s msxml4.dll regsvr32 /s msxml6.dll net start swprv net start vss Note: Exact DLL names and steps vary by Windows version. Consult Microsoft docs when in doubt.
Interpreting common errors
- 0x80042306 — VSS provider is in an inconsistent state; restart providers and service.
- 0x80042308 — No shadow copies could be created; check disk space and shadow storage.
- Writer in Failed state — identify which application writer (e.g., SQL, Exchange) and restart its service or application. Often a service restart or scheduled maintenance clears transient failures.
When Acronis VSS Doctor can’t fix the problem
- Persistent writer failures tied to application-level corruption (e.g., a corrupt database) require application-specific repair.
- Hardware provider issues (third-party storage hardware snapshot providers) may need vendor-specific tools or updates.
- If registry or system components are heavily corrupted, consider system repair/restore.
Best practices to prevent VSS issues
- Keep Windows and VSS-aware applications up to date (hotfixes and service packs).
- Monitor Event Viewer for early VSS warnings.
- Ensure sufficient free disk space and configure shadow storage appropriately.
- Avoid third-party VSS providers unless required; test providers in a lab before production use.
- Schedule backups during low-load periods and regularly restart long-running services to clear resource leaks.
Logs and escalation
- Collect: Acronis logs (from the product UI or installation folder), Windows Event Viewer (Application/System), and VSS Doctor output.
- If escalating to Acronis support or Microsoft, provide timestamps, exact error codes, the list of VSS writers/providers and their states, and recent system changes.
Quick checklist
- Run Acronis VSS Doctor as admin.
- Review writers/providers; attempt automated repair.
- Restart VSS and related services.
- Re-register VSS components if needed.
- Check disk/shadow storage and application-specific logs.
If you want, I can: run through a sample troubleshooting session with specific Windows/backup error codes you have, produce a script to re-register VSS components for a particular Windows version, or draft an email with logs formatted for Acronis support.
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