How to fix Error 9920 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 9920 — Failed to Get MSFTESQL Indexer Interface for Full-Text Catalog

Why This Error Happens

This error typically occurs when the SQL Server Full-Text Filter Daemon Launcher service (or the underlying full-text engine component) is stopped, disabled, or fails to communicate with the Database Engine due to permission issues on the service account. It can also result from a corrupted or inaccessible full-text catalog directory, or from a mismatch/corruption in the full-text component registration after a patch, upgrade, or improper shutdown. In clustered or AlwaysOn environments, this can additionally stem from the full-text service not being properly failed over or started on the active node.

Step-by-Step Resolution Guide

Step 1: Verify the Full-Text Filter Daemon Launcher Service Status

  • Open Services.msc on the Windows Server 2025 / Windows 11 host.
  • Locate SQL Full-text Filter Daemon Launcher (MSSQLSERVER) (or the named instance equivalent).
  • Ensure the service Startup Type is set to Automatic and the service is currently Running.
  • If stopped, right-click and select Start, then recheck the application for the 9920 error.

Step 2: Validate Service Account Permissions

  • Confirm the service account running the Full-Text Daemon Launcher has read/write access to the full-text catalog directory, typically located at:
    C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\FTData\
  • Open Component Services (dcomcnfg) > Computers > My Computer > DCOM Config, locate MSSQLFDLauncher, right-click > Properties > Security tab, and verify the SQL service account has Local Launch and Local Activation permissions.
  • Restart the SQL Server service after applying changes.

Step 3: Rebuild the Full-Text Catalog

  • Open SQL Server Management Studio (SSMS) and connect to the affected instance.
  • Run the following T-SQL command to rebuild the problematic catalog:
  ALTER FULLTEXT CATALOG [YourCatalogName] REBUILD;
  • If the catalog is severely corrupted, drop and recreate it:
  DROP FULLTEXT CATALOG [YourCatalogName];
  CREATE FULLTEXT CATALOG [YourCatalogName] AS DEFAULT;

Step 4: Repair SQL Server Full-Text Component Registration

  • Launch SQL Server Installation Center from the Start Menu.
  • Select Maintenance > Repair, choose the affected instance, and allow the installer to fix corrupted Full-Text Search binaries.
  • Reboot the server once the repair completes to reinitialize the MSFTESQL interface.

Step 5: Check Windows Event Viewer for Underlying Errors

  • Open Event Viewer > Windows Logs > Application.
  • Filter for Source: MSSQLSERVER and cross-reference timestamps with Error 9920 occurrences.
  • Look for related errors (e.g., Event ID 7, 17055) indicating file corruption or access denial that may need separate remediation.

Alternative or Verification Steps

  • After applying fixes, run SELECT * FROM sys.fulltext_catalogs; in SSMS to confirm the catalog status shows as Online/Idle rather than Error.
  • If the issue persists, consider fully uninstalling and reinstalling the Full-Text and Semantic Extractions for Search feature via SQL Server Setup, then recreate catalogs and indexes from scratch.