diff --git a/src/calibre/ebooks/oeb/polish/toc.py b/src/calibre/ebooks/oeb/polish/toc.py index 465c6821f0..1b6c216a67 100644 --- a/src/calibre/ebooks/oeb/polish/toc.py +++ b/src/calibre/ebooks/oeb/polish/toc.py @@ -546,7 +546,7 @@ def commit_nav_toc(container, toc, lang=None): from calibre.ebooks.oeb.polish.pretty import pretty_xml_tree tocname = find_existing_nav_toc(container) if tocname is None: - item = container.generate_item('nav.html', id_prefix='nav') + item = container.generate_item('nav.xhtml', id_prefix='nav') item.set('properties', 'nav') tocname = container.href_to_name(item.get('href'), base=container.opf_name) try: