How to fix Error 6927 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 6927 – XML Validation: Invalid Simple Type Value

Why This Error Happens

Error 6927 occurs when SQL Server 2025 attempts to validate an XML instance against an XML Schema Collection (XSD), but a node’s value does not conform to the simple type defined in the schema (e.g., a string value placed where an xs:integer, xs:date, or xs:boolean is expected). This typically happens due to malformed data being inserted into a typed XML column, locale/culture mismatches in date or numeric formatting, or a corrupted/outdated XML Schema Collection that no longer matches the application’s data contract. It can also surface after an in-place upgrade to SQL Server 2025 if stricter XSD compliance checks were introduced for existing schema collections.

Step-by-Step Resolution Guide

Step 1: Identify the Offending XML Data and Schema

  • Run the failing INSERT/UPDATE statement in isolation using SQL Server Management Studio (SSMS) connected to your SQL Server 2025 instance to capture the exact %ls value reported in the error message.
  • Query the schema collection in use with: SELECT xml_schema_namespace(N'dbo', N'YourSchemaCollectionName');
  • Cross-reference the failing value against the <xs:simpleType> or <xs:restriction> definitions (base type, pattern, enumeration) in the retrieved XSD output.

Step 2: Correct the Data Format or Type Mismatch

  • Adjust the source application or ETL process to format values according to the XSD-defined type (e.g., ensure dates are YYYY-MM-DD for xs:date, booleans are lowercase true/false, not 1/0 or True).
  • For numeric types, verify no thousands separators or currency symbols are present in the XML payload.
  • Re-test the insert using a minimal XML sample in SSMS: DECLARE @x XML(YourSchemaCollection) = '<Root><Value>123</Value></Root>';

Step 3: Repair or Update the XML Schema Collection

  • If the schema itself is outdated or too strict, drop and recreate it using DROP XML SCHEMA COLLECTION YourSchemaCollectionName; followed by CREATE XML SCHEMA COLLECTION with the corrected XSD definition.
  • Store the updated XSD file in a version-controlled location (e.g., C:\SQLSchemas\YourApp\schema_v2.xsd on the Windows Server 2025 host) for change tracking.
  • Ensure the SQL Server service account has read access to any referenced external XSD import paths if schemas use xs:import or xs:include.

Step 4: Apply Latest SQL Server 2025 Cumulative Update

  • Open Windows Update or check the SQL Server Installation Center on Windows Server 2025 / Windows 11 for pending Cumulative Updates (CUs), as XML validation engine fixes are periodically released.
  • Verify current build version with: SELECT @@VERSION; and compare against Microsoft’s latest CU release notes for SQL Server 2025.
  • Restart the SQL Server service (services.msc → SQL Server (MSSQLSERVER) → Restart) after applying any update.

Alternative or Verification Steps

  • Verify the fix by re-running the original failing transaction and confirming no Error 6927 appears in the SQL Server Error Log (Get-Content "C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG" -Tail 50 in PowerShell).
  • As an alternative, if strict validation is not business-critical, temporarily store the data as untyped XML (without a schema collection binding) and apply validation at the application layer instead.