Skip to content
EPUBCheck · NCX (EPUB 2 table of contents)

NCX-006

Updated:

EPUBCheck NCX-006 is a usage message: “Empty "text" label in the NCX document.” An NCX navigation entry has an empty text label, so the table of contents shows a blank line.

The official message

Empty "text" label in the NCX document

Default severity
Usage. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.
EPUBCheck version
5.4.0

Typical causes

  • Entries generated from headings that had no text, such as image-only headings.

How to fix it

  • Give every navLabel a text, or remove the entry.

Terms used here

Other NCX messages

  • NCX-004 NCX identifier ("dtb:uid" metadata) should not contain leading or trailing whitespace.
  • NCX-001 NCX identifier ("…") does not match OPF identifier ("…").

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EPUBLab.

FAQ

What does EPUBCheck NCX-006 mean?

EPUBCheck NCX-006 is a usage message: “Empty "text" label in the NCX document.” An NCX navigation entry has an empty text label, so the table of contents shows a blank line.

Is NCX-006 an error?

NCX-006 is reported as usage by default. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.