Problem Description
SQL restore jobs may fail during execution during the restore preparation phase. The restore workflow initializes successfully, including SQL connectivity, VDI communication, and restore services, but the operation fails while initializing the Windows Volume Shadow Copy Service (VSS).
Cause
This issue occurs when the Windows Volume Shadow Copy Service (VSS) subsystem on the destination SQL server encounters unexpected errors during restore initialization.
The failure is typically related to:
Unstable or failed VSS writers
Corrupted VSS components
SQL Server VSS Writer service issues
Conflicts with third-party backup, replication, or snapshot applications
Stuck or inconsistent legacy VSS snapshots
Storage or disk-related issues (insufficient space/corruption)
Operating system-level VSS failures
Note: The restore workflow cannot proceed if the host OS VSS framework fails to initialize successfully.
Traceback
level=error message="Failed to initialize vss restore" error="VSS_E_UNEXPECTED - A volume shadow copy service (VSS) component encountered an unexpected error."
level=error message="failed to initialize VSS Restore" Code=7014
level=error message="Failed to prepare for restore"
Typical Observations
SQL connectivity validation succeeds.
Required restore services are running normally.
Failure occurs specifically during VSS initialization.
Restore workflow aborts immediately after VSS initialization failure.
Primary error identified:
VSS_E_UNEXPECTED
Resolution
Perform the following verification and troubleshooting steps on the destination SQL server.
Step 1: Verify VSS Writers Status
Run the following command from an elevated Command Prompt:
vssadmin list writers
Verify that:
All VSS writers are in a [1] Stable state.
No writers show a Failed or Timed Out status (specifically check
SqlServerWriter).
Step 2: Restart VSS-Related Services
If any writers show errors or are unresponsive, restart the VSS-related services via Command Prompt:
DOS
net stop vss net stop sqlwriter
net start sqlwriter net start vss
Alternatively, you can manage these via the Windows Services console (services.msc):
Locate Volume Shadow Copy and change/verify its status.
Locate SQL Server VSS Writer and restart it.
Step 3: Reboot the Server
If restarting the services does not clear the faulty writer states:
Schedule a reboot of the destination SQL server during an approved maintenance window.
Retry the restore operation immediately after the system boots.
Step 4: Review Windows Event Logs
Open the Windows Event Viewer (eventvwr.msc) and navigate to:
Windows Logs > Application
Windows Logs > System
Filter or review logs around the exact timestamp of the failure for errors originating from:
VSSVolSnapSQLWriterDiskor storage subsystems
Step 5: Check for Third-Party Backup or Snapshot Tools
Verify whether any other third-party backup, replication, or storage snapshot applications are running concurrently or interacting with the host's VSS subsystem. Conflicting applications can lock or interfere with:
VSS writer availability
Snapshot creation frameworks
Restore initialization sequences
Step 6: Validate Disk Health and Free Space
Ensure that the destination volumes have adequate space and are free of filesystem errors:
Sufficient free disk space is available for the database expansion.
Destination volumes are healthy.
Run the following checks to verify storage status:
chkdsk
wmic logicaldisk get size,freespace,caption
Step 7: Retry the Restore Operation
After completing and validating the above steps:
Re-trigger the SQL restore job from the Druva Management Console.
Monitor live restore logs to confirm successful VSS initialization.