How to fix Error 5139 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5139

Why This Error Happens

Error 5139 occurs when SQL Server attempts to perform a file operation (such as creating, attaching, or growing a database file) and the underlying Windows operating system rejects the request. This is most commonly caused by insufficient NTFS permissions for the SQL Server service account, a file path that no longer exists or is misspelled, or the target file/disk being locked, offline, or read-only. In clustered or storage-replica environments, this can also surface when the disk volume hosting the data file has failed over or lost connectivity.

Step-by-Step Resolution Guide

Step 1: Verify the File Path and Disk Availability

  • Open File Explorer or run dir from Command Prompt to confirm the file path referenced in the error (e.g., D:\SQLData\MyDB.mdf) actually exists.
  • Check Disk Management (diskmgmt.msc) to ensure the volume is online, not read-only, and has sufficient free space.
  • If using mount points or SAN storage, confirm the LUN is attached and visible to Windows Server 2025.

Step 2: Correct NTFS and Service Account Permissions

  • Open the properties of the folder containing the database files, go to the Security tab, and confirm the SQL Server service account (e.g., NT Service\MSSQLSERVER or a custom domain account) has Full Control.
  • Use PowerShell to quickly audit permissions:
  Get-Acl "D:\SQLData" | Format-List
  • If permissions are missing, grant access via:
  icacls "D:\SQLData" /grant "NT SERVICE\MSSQLSERVER:(OI)(CI)F" /T

Step 3: Check for File Locks or Conflicting Processes

  • Use Resource Monitor (resmon.exe) or handle.exe (Sysinternals) to confirm no other process (antivirus, backup agent, or another SQL instance) has the file locked.
  • Temporarily disable real-time antivirus scanning on the SQL data/log directories to rule out interference.
  • Restart the SQL Server service after confirming no locks exist:
  net stop MSSQLSERVER
  net start MSSQLSERVER

Step 4: Review Windows Event Viewer for the Underlying OS Error Code

  • Open Event Viewer > Windows Logs > System and Application to find the specific Windows error number referenced in the SQL error message (e.g., Error 5 = Access Denied, Error 32 = Sharing Violation).
  • Cross-reference the OS error code with Microsoft’s documentation to pinpoint whether it’s a permissions, locking, or hardware-level issue.
  • Resolve based on the specific code (e.g., re-grant permissions for Error 5, release locks for Error 32).

Alternative or Verification Steps

  • After applying fixes, attempt the original operation again (e.g., CREATE DATABASE, ALTER DATABASE ... MODIFY FILE, or restore) and confirm it completes without Error 5139.
  • If the issue persists, run DBCC CHECKDB and review the SQL Server Error Log (sqlerrlog) for additional context, or move the database files to a different, verified-healthy volume as a workaround.