We consider following guidelines when specifying a schema file to validate our XML.
1) If we are validating an XML file using a schema defined in the XML file, the schema can be defined with an absolute or relative path. When we specify a relative path, QTP searches for the schema in the folders listed in the Folders tab of the Options dialog box.
2) If we are validating an XML document located on the Web with a schema file located on our file system, we cannot use UNC format (for example, ComputerNamePathToSchema) to specify the schema file location. Instead, map the schema file location to a network drive.
3) If there is a schema with a namespace defined in our XML document, the namespace of the external schema must be identical to the one defined in our document.
4) When we perform a schema validation, QTP validates all of the elements in the XML document, even if certain XML elements are not associated with a schema file. Any XML elements that are not associated with a schema file will cause the schema validation to fail.