FileExamples
CriticalXML · .xml

XML Unclosed Tags — Missing End Elements

An XML file with opening tags that are never closed, violating the well-formedness requirement of XML.

Why It Fails

XML requires every opening tag to have a corresponding closing tag (or be self-closing). Unclosed tags make the document not well-formed, and all compliant XML parsers must reject it.

Broken Example

<?xml version="1.0" encoding="UTF-8"?>
<catalog>
  <book>
    <title>XML Guide</title>
    <author>John Doe
  </book>
</catalog>

Expected Error Behavior

Parser throws 'expected end tag' or 'not well-formed' error. The error typically points to the end of the file or the next mismatched tag.

Affected Software

All XML parsersWeb browsers (XHTML)SOAP servicesSVG renderers

How to Fix

Close all tags properly. Use an XML validator to find unclosed tags. IDEs with XML support highlight these automatically.