Quick answer
An XSD schema is an XML document.
Invalid XSD Schema
An XSD schema is an XML document. If the XSD itself is not well-formed (unclosed tags, wrong nesting, invalid attributes), validators cannot load it and will report an error.
Common causes
- Unclosed element or missing closing tag in the XSD.
- Mismatched opening and closing tag names (e.g. <xs:element> closed with </xs:complexType>).
- Invalid or unquoted attribute in an XSD element.
How to fix
- Ensure every <xs:...> tag has a matching </xs:...> with the same name.
- Quote all attribute values (e.g. name="root", type="xs:string").
- Validate the XSD as plain XML first with an XML validator to get line and column.
Examples
Bad
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="r" type="xs:string" </xs:schema>
Good
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="r" type="xs:string"/> </xs:schema>
FAQ
- Is XSD valid XML?
- Yes. An XSD document is XML; it must be well-formed before a validator can use it as a schema.
- What namespace does XSD use?
- W3C XML Schema uses http://www.w3.org/2001/XMLSchema, typically with the xs: prefix.
Fix it now
Try in validator (prefill this example)