How to fix Error 1476 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 1476 – Database Mirroring Timeout Value Exceeds Maximum

Why This Error Happens

This error occurs when the ALTER DATABASE SET PARTNER TIMEOUT value specified during database mirroring configuration exceeds the maximum allowable threshold of 32767 seconds. SQL Server 2025 enforces this upper boundary because the timeout value is stored internally as a signed 16-bit integer, and any value beyond this range causes an overflow during validation. This typically results from a manual scripting error, a misconfigured automation/deployment template, or a copy-paste mistake from a legacy T-SQL script that used an incompatible or arbitrary large value.

Step-by-Step Resolution Guide

Step 1: Identify the Offending T-SQL Statement

  • Review the script or job that triggered the error, typically an ALTER DATABASE [YourDB] SET PARTNER TIMEOUT command.
  • Check SQL Server Agent job history or deployment pipeline logs (e.g., Azure DevOps, Jenkins) for the exact value passed.
  • Confirm the value in question by searching for TIMEOUT followed by a numeric parameter in the script.

Step 2: Correct the Timeout Value

  • Edit the script to use a valid timeout value between 1 and 32767 seconds (the default is 10 seconds).
  • Example corrected syntax:
  ALTER DATABASE [YourDatabaseName] SET PARTNER TIMEOUT 30;
  • Avoid using large placeholder values (e.g., 99999 or 2147483647) that were likely inherited from unrelated timeout configurations (such as connection or command timeouts).

Step 3: Validate Mirroring Configuration via SSMS

  • Open SQL Server Management Studio (SSMS) and connect to the principal server instance.
  • Navigate to Database Properties > Mirroring page to confirm the timeout field reflects a valid number.
  • Re-run the corrected script against the principal database only (timeout settings are not configured on the mirror).

Step 4: Re-deploy Through Automation Tools (If Applicable)

  • If the error originated from an Infrastructure-as-Code template (DSC, Terraform, or PowerShell DSC resource for SQL mirroring), update the hardcoded or variable-driven timeout parameter in the configuration file.
  • Re-run the deployment pipeline and monitor the SQL Server error log (%ProgramFiles%\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG) for confirmation that mirroring initialized without error.

Alternative or Verification Steps

  • Run SELECT mirroring_connection_timeout FROM sys.database_mirroring WHERE database_id = DB_ID('YourDatabaseName'); to confirm the active timeout value is within range and successfully applied.
  • If the error persists despite correcting the value, verify there isn’t a separate Availability Group or Always On configuration script conflicting with legacy mirroring syntax, as SQL Server 2025 deprecates classic mirroring in favor of Always On Availability Groups for most production scenarios.