system AI diagnostic case

Windows 11 25H2 SQL Server Machine Learning Services Python Not Starting

This diagnostic page addresses the issue where Python integration in SQL Server Machine Learning Services fails to start on Windows 11 version 25H2. It highlights specific Windows components, services, and logs relevant to troubleshooting this problem.

Describe your Windows problem
Read-only diagnostic first. No repair without review.

Symptoms

  • Python scripts fail to execute within SQL Server Machine Learning Services
  • SQL Server Machine Learning Services external script execution errors referencing Python
  • No Python process spawned when running sp_execute_external_script with Python language
  • Event Viewer logs show errors related to the Machine Learning Runtime or Python Host

Likely causes

  • Python runtime environment for SQL Server Machine Learning Services is corrupted or missing
  • Windows Defender or third-party antivirus blocking Python executable or related DLLs
  • SQL Server Launchpad service not running or misconfigured
  • Incompatibility or missing Windows updates affecting Machine Learning Services components

What FixWin checks

  • Verify that the SQL Server Launchpad service (SQLSERVERLAUNCHPAD) is running
  • Check Windows Defender or antivirus quarantine for Python or Machine Learning Services binaries
  • Inspect Event Viewer logs under 'Application' and 'Microsoft-SQLServer' for related errors
  • Confirm that the Machine Learning Services feature with Python support is installed via SQL Server setup
  • Validate that the Python installation folder used by SQL Server exists and contains expected files

AI diagnostic workflow

  • Open Services.msc and locate SQL Server Launchpad service; ensure it is started and set to Automatic
  • Review Event Viewer logs: navigate to Application logs and filter by source 'SQLSERVERAGENT' and 'SQLSERVERLAUNCHPAD' for errors
  • Run 'sp_configure' in SQL Server Management Studio to verify 'external scripts enabled' is set to 1
  • Check Windows Defender Security Center for any blocked or quarantined files related to Python or SQL Server
  • Use PowerShell to verify presence and permissions of Python installation directory under SQL Server folders (e.g., C:\Program Files\Microsoft SQL Server\MSSQL15.MSSQLSERVER\PYTHON_SERVICES)

Related Windows entities

  • SQL Server Launchpad (SQLSERVERLAUNCHPAD) service
    This Windows service manages execution of external scripts including Python for SQL Server Machine Learning Services.
  • Event Viewer - Microsoft-SQLServer Logs log
    Contains detailed error messages and operational logs for SQL Server components including Machine Learning Services.
  • Windows Defender Antivirus component
    May block or quarantine Python executables or DLLs used by SQL Server Machine Learning Services, preventing startup.
  • Machine Learning Services Feature package
    SQL Server feature that enables execution of Python and R scripts; must be installed and properly configured.
  • sp_configure 'external scripts enabled' tool
    SQL Server configuration option that enables or disables execution of external scripts like Python.

Repair logic

Begin by confirming that SQL Server Launchpad service is running and configured correctly, as it is responsible for launching Python scripts. Next, inspect Event Viewer logs for any errors related to Machine Learning Services or Python runtime failures. Check antivirus or Windows Defender settings to ensure Python executables are not blocked or quarantined. Verify that SQL Server Machine Learning Services with Python support is installed and that the 'external scripts enabled' configuration is set to 1. Finally, confirm the Python runtime directory used by SQL Server exists and has correct permissions. Address any anomalies found during these checks to restore Python startup functionality within SQL Server Machine Learning Services.

FAQ

Why does Python not start when running sp_execute_external_script in SQL Server on Windows 11 25H2?

Common reasons include the SQL Server Launchpad service not running, missing or corrupted Python runtime files, or antivirus software blocking the Python executable.

How can I check if SQL Server Launchpad service is running?

Open Services.msc, locate 'SQL Server Launchpad' (SQLSERVERLAUNCHPAD), and verify its status is 'Running' and startup type is set to 'Automatic'.

Can Windows updates affect SQL Server Machine Learning Services Python integration?

Yes, certain Windows updates can impact dependencies or security settings that affect Machine Learning Services components, so ensure your system is fully updated and compatible.

Related Windows problems

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