How to fix Error 3938 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 3938 (FILESTREAM Transaction Conflict)

Why This Error Happens

Error 3938 occurs when a transaction attempts to access or modify a FILESTREAM data stream while that same transaction is concurrently executing a close operation on the file handle. This typically happens because an application closed a FILESTREAM handle using TxFSetTransactionStatus or let the handle fall out of scope before the parent transaction was explicitly committed or rolled back. SQL Server detects this race condition between the Win32 file handle closure and the transactional context, forcing a rollback to preserve data consistency between the structured data and the unstructured FILESTREAM data.

Step-by-Step Resolution Guide

Step 1: Audit Application Code for Handle Management

  • Review the client application (C#, C++, or PowerShell scripts) handling FILESTREAM data retrieval.
  • Ensure every SqlFileStream object (.NET) is wrapped in a using statement to guarantee disposal occurs before the SqlTransaction.Commit() method is called.
  • Verify that no asynchronous threads are holding the file handle open while the main thread attempts to commit the transaction.

Step 2: Verify Transaction Isolation Levels

  • Open SQL Server Management Studio (SSMS) 21 and connect to the Windows Server 2025 instance.
  • Check if the session is running under READ_COMMITTED_SNAPSHOT or SNAPSHOT isolation, as high concurrency under these levels can increase the likelihood of handle conflicts.
  • Run the following query to check current settings:
 SELECT name, snapshot_isolation_state_desc, is_read_committed_snapshot_on FROM sys.databases WHERE name = 'YourDBName';

Step 3: Reset the FILESTREAM Filegroup Configuration

  • Navigate to the SQL Server Configuration Manager on Windows Server 2025.
  • Right-click the SQL Server service instance and select Properties, then navigate to the FILESTREAM tab.
  • Toggle off “Enable FILESTREAM for Transact-SQL access,” apply the change, and re-enable it to clear any stuck I/O handles in the Windows Kernel Transaction Manager (KTM).
  • Restart the SQL Server (MSSQLSERVER) service via services.msc to apply the KTM reset.

Step 4: Check Antivirus and Windows Defender Exclusions

  • Navigate to Windows Security > Virus & threat protection > Manage settings > Exclusions.
  • Add an exclusion for the specific FILESTREAM data container path (e.g., D:\SQLData\FileStreamContainer).
  • This prevents real-time scanning engines from locking the file handle externally while SQL Server attempts to close it within the transaction scope.

Alternative or Verification Steps

  • Verification: Re-run the specific stored procedure or application workflow that triggered the error while monitoring Extended Events (XEvents) for the filestream_transaction_log event to confirm the handle closes cleanly without triggering the 3938 rollback.
  • Alternative: If the error persists in high-throughput environments, consider migrating the logic to use FileTable instead of raw FILESTREAM columns, as FileTable manages the Win32 handle lifecycle automatically, reducing manual transaction-scope errors.