How to fix Error 4068 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 4068 – “sp_resetconnection was sent as part of a remote procedure call (RPC) batch”

Why This Error Happens

This error occurs when a client driver (such as an outdated ODBC or OLE DB provider) attempts to bundle the internal sp_resetconnection call within the same RPC batch as a user-defined stored procedure call, which SQL Server 2025’s stricter protocol parser now rejects. It is typically triggered by legacy connection pooling logic in older client libraries that have not been updated to align with the TDS (Tabular Data Stream) protocol changes introduced in this release. Additionally, this can surface when middleware or connection pooling software reuses a connection improperly, sending a reset command alongside a batched procedure call rather than as a standalone operation.

Step-by-Step Resolution Guide

Step 1: Update Client Drivers and Connectivity Components

  • Navigate to the application server and check the installed version of msodbcsql.msi or Microsoft.Data.SqlClient via Control Panel > Programs and Features.
  • Download and install the latest Microsoft ODBC Driver (18.5 or higher) or update the NuGet package Microsoft.Data.SqlClient to version 6.0+ in your application project.
  • Restart the application pool or service referencing the driver (iisreset if applicable).

Step 2: Disable Connection Pooling Temporarily to Isolate the Issue

  • Open your application’s connection string configuration file (e.g., web.config, app.config, or appsettings.json).
  • Add or modify the parameter: Pooling=False; to test if the issue persists without pooled connections reusing the reset command improperly.
  • Monitor SQL Server logs at C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG for recurrence of Error 4068.

Step 3: Apply the Latest SQL Server 2025 Cumulative Update

  • Open SQL Server Configuration Manager and confirm the current build number via SELECT @@VERSION; in SQL Server Management Studio (SSMS).
  • Visit the Microsoft Update Catalog and download the latest Cumulative Update (CU) package for SQL Server 2025.
  • Run the installer as Administrator and follow the prompts to patch the instance, then restart the SQL Server (MSSQLSERVER) service via services.msc.

Step 4: Review and Correct Application-Level RPC Batching Logic

  • Inspect the application source code or stored procedure call wrapper for instances where sp_executesql or raw RPC calls are manually concatenated with reset logic.
  • Ensure that calls to stored procedures use parameterized SqlCommand objects with CommandType.StoredProcedure rather than raw batched SQL strings.
  • Remove any custom connection-reset wrapper code that manually injects sp_resetconnection into a batch.

Alternative or Verification Steps

  • To verify the fix, run a load test using SQL Server Profiler or Extended Events to capture RPC:Completed events and confirm sp_resetconnection no longer appears bundled with user procedure calls.
  • If the error persists after driver and CU updates, as a temporary workaround, configure the application’s connection pool to set Connection Lifetime=0 and Max Pool Size to a lower value to reduce aggressive connection reuse cycles.