How to fix Error 11274 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 11274 – Corrupted Message, Sequence Number Exceeds Allowed Limit

Why This Error Happens

This error occurs within Service Broker when a message fragment arrives with a sequence number that falls outside the expected range for its conversation, typically indicating the underlying TCP transport delivered corrupted or out-of-order packet data. It can be triggered by network-level corruption between endpoints, a mismatched or outdated Service Broker protocol implementation after an upgrade, or physical corruption in the sys.conversation_endpoints internal fragment reassembly buffer. In rare cases, faulty NIC drivers or aggressive packet offloading features (like TCP Chimney or RSS misconfiguration) on Windows Server 2025 corrupt packets in transit without Windows flagging a transport-layer failure.

Step-by-Step Resolution Guide

Step 1: Identify and End the Corrupted Conversation

  • Run the following query to locate the offending Conversation ID referenced in the error message:
  SELECT conversation_handle, far_service, state_desc 
  FROM sys.conversation_endpoints 
  WHERE conversation_id = '<GUID-from-error-message>';
  • End the broken conversation cleanly to prevent repeated retries:
  END CONVERSATION '<conversation_handle>' WITH CLEANUP;
  • Check sys.transmission_queue for stuck messages tied to the same handle and clear them if necessary.

Step 2: Validate Network Transport and Disable Offloading Features

  • Open PowerShell as Administrator and disable TCP Chimney Offload, which is known to corrupt packet sequencing on Windows Server 2025:
  netsh int tcp set global chimney=disabled
  netsh int tcp set global rss=disabled
  • Update or roll back the NIC driver via Device Manager if the server recently received a Windows Update that touched network components.
  • Re-enable RSS only after confirming stability, as disabling it fully can impact throughput on high-traffic SQL Server instances.

Step 3: Rebuild Service Broker Routing and Verify Certificates

  • Confirm that Service Broker is enabled and functioning on the database:
  SELECT is_broker_enabled FROM sys.databases WHERE name = 'YourDatabaseName';
  • If disabled or inconsistent, re-enable it:
  ALTER DATABASE YourDatabaseName SET ENABLE_BROKER WITH ROLLBACK IMMEDIATE;
  • Verify that dialog security certificates haven’t expired, as expired certs can cause message fragment corruption during re-authentication handshakes.

Step 4: Apply the Latest SQL Server 2025 Cumulative Update

  • Navigate to the Microsoft Update Catalog and download the latest Cumulative Update (CU) for SQL Server 2025, as Service Broker sequencing bugs are frequently patched in CU releases.
  • Install the update on all nodes involved in the conversation (both initiator and target instances).
  • Restart the MSSQLSERVER service via services.msc or:
  Restart-Service -Name MSSQLSERVER -Force

Alternative or Verification Steps

  • After applying fixes, monitor the SQL Server Error Log and Windows Event Viewer (Application log) for 24–48 hours to confirm Error 11274 does not recur under normal message load.
  • If the issue persists only between specific servers, test with a direct crossover network path or a different physical NIC to isolate whether the corruption is hardware-based rather than software-based.