How to fix Error 5511 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5511 – FILESTREAM File System Log Record Corrupted

Why This Error Happens

This error occurs when the FILESTREAM file system log record on disk has become corrupted, typically due to an unexpected shutdown, storage-level failure, or disk I/O error that interrupted a write operation to the log folder. It can also result from antivirus software or backup tools locking or modifying files within the FILESTREAM container while SQL Server was writing metadata. In some cases, this is triggered by underlying NTFS volume corruption or a mismatch between the FILESTREAM data container and its transaction log tracking records.

Step-by-Step Resolution Guide

Step 1: Verify the Scope of Corruption

  • Check SQL Server Error Log and Windows Event Viewer (Application log) for the exact FILESTREAM container path referenced alongside Error 5511.
  • Note the database name and the associated FILESTREAM filegroup logical path (query sys.database_files where type_desc = 'FILESTREAM').
  • Attempt to take the database offline cleanly: ALTER DATABASE [YourDB] SET OFFLINE WITH ROLLBACK IMMEDIATE;

Step 2: Run Disk and File System Diagnostics

  • Open an elevated PowerShell/Command Prompt and run chkdsk X: /f /r (replace X: with the volume hosting the FILESTREAM container) to repair NTFS-level corruption.
  • Confirm the disk subsystem health using Get-PhysicalDisk | Get-StorageReliabilityCounter to rule out hardware degradation.
  • If using a SAN or virtualized disk, verify no underlying storage replication or snapshot conflicts occurred recently.

Step 3: Exclude FILESTREAM Paths from Antivirus and Backup Agents

  • Navigate to your antivirus console and add an exclusion for the full FILESTREAM data container path (e.g., D:\SQLData\FileStreamContainer\).
  • Exclude the same path from third-party backup agents or file-indexing services (e.g., Windows Search Indexer).
  • Restart the SQL Server service (services.msc → SQL Server (MSSQLSERVER) → Restart) after applying exclusions.

Step 4: Restore from a Known-Good Backup

  • If corruption persists, perform a restore using the most recent full backup that includes the FILESTREAM filegroup: RESTORE DATABASE [YourDB] FROM DISK = 'E:\Backups\YourDB.bak' WITH REPLACE;
  • Apply any available transaction log backups to minimize data loss.
  • Validate the FILESTREAM container rebuilds correctly by checking the folder structure matches the $FSLOG and $FSDATA markers under the container root.

Step 5: Rebuild the FILESTREAM Filegroup (If Restore Is Not Viable)

  • Remove the corrupted FILESTREAM file reference: ALTER DATABASE [YourDB] REMOVE FILE [FileStreamLogicalName];
  • Re-add a new FILESTREAM container: ALTER DATABASE [YourDB] ADD FILE (NAME = 'NewFSContainer', FILENAME = 'D:\SQLData\NewFileStreamContainer') TO FILEGROUP [FileStreamGroup];
  • Migrate any recoverable BLOB data manually from the old container before deleting it.

Alternative or Verification Steps

  • Run DBCC CHECKDB('YourDB') WITH ALL_ERRORMSGS, NO_INFOMSGS; after remediation to confirm no further corruption is reported, and bring the database back ONLINE.
  • If Error 5511 recurs immediately after remediation, treat it as a hardware-level storage issue — run full chkdsk with bad sector scanning and consider relocating the FILESTREAM container to a different physical volume.