How to fix Error 10227 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 10227

Why This Error Happens

Error 10227 occurs when a data manipulation statement (UPDATE or INSERT) attempts to modify a computed column, a column defined with a persisted rule, or a field marked as read-only within a CLR user-defined type (UDT). SQL Server 2025 enforces strict metadata validation on these field types, rejecting any direct write operation that bypasses the defined computation logic or assembly method. This typically surfaces after a schema migration, a CLR assembly update, or when application code (ORM-generated SQL) incorrectly includes read-only columns in its UPDATE/INSERT column list.

Step-by-Step Resolution Guide

Step 1: Identify the Offending Column and Type Definition

  • Open SQL Server Management Studio (SSMS) and run the following query to inspect the table schema:
  SELECT name, is_computed, system_type_id 
  FROM sys.columns 
  WHERE object_id = OBJECT_ID('YourSchema.YourTableName');
  • Check the is_computed flag; if it returns 1, the column is computed and cannot be targeted directly in an UPDATE statement.
  • Cross-reference the %.*ls.%.*ls type referenced in the Event ID 10227 log entry with sys.assembly_types if a CLR UDT is involved.

Step 2: Correct the Application Query Logic

  • Modify the application or stored procedure code to exclude the read-only/computed column from the explicit column list in the INSERT INTO (...) or SET clause.
  • If using an ORM (e.g., Entity Framework, Dapper), update the model/mapping configuration to mark the specific property as [DatabaseGenerated(DatabaseGeneratedOption.Computed)] or equivalent, preventing the framework from generating write operations for that field.
  • Example of a corrected query:
  -- Incorrect: UPDATE Orders SET TotalPrice = 100, OrderDate = GETDATE()
  -- Corrected: UPDATE Orders SET OrderDate = GETDATE() 
  -- (Assuming TotalPrice is a computed column)

Step 3: Validate CLR Assembly Permissions (If Applicable)

  • If the error originates from a CLR User-Defined Type method marked as IsMutator = false, verify the assembly permission set in SQL Server 2025.
  • Navigate to Object Explorer > Databases > YourDB > Programmability > Assemblies.
  • Right-click the specific assembly, select Properties, and ensure the Permission Set is correctly configured (e.g., SAFE or EXTERNAL_ACCESS) depending on the UDT’s requirements, as misconfigured permissions can sometimes trigger metadata locks that mimic this error.

Step 4: Rebuild Views or Dependent Objects

  • If the computed column definition was recently altered, stale metadata in dependent views might cause this error.
  • Run sp_refreshview on all views referencing the table in Windows Server 2025 environments to force a metadata refresh:
  EXEC sp_refreshview 'YourSchema.YourViewName';

Alternative or Verification Steps

  • Verify the Fix: Re-run the original UPDATE or INSERT statement in a test environment (Windows 11 development instance or SSMS query window) after removing the read-only column from the query; a successful execution with “Rows affected” confirms resolution.
  • Alternative Solution: If the column must programmatically receive a value, consider dropping the COMPUTED constraint and replacing the logic with an INSTEAD OF trigger that handles the calculation separately from the direct write command.