Schema Validation in Visual Studio
After you have finished creating a schema, or at different times during its creation, you can validate it to determine whether it contains any internal inconsistencies, or has other issues that might prevent it from being used effectively for process instance messages.
To validate a schema, use the Validate Schema command on the shortcut menu associated with the schema in Solution Explorer. The results of the validation are reported in the Visual Studio Output window.
For detailed step-by-step instructions regarding how to validate a schema, see Validating Schemas.