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EPUBCheck · Resources and references

RSC-012

Updated:

EPUBCheck RSC-012 is an error message: “Fragment identifier is not defined.” A link points to a fragment (#id) that does not exist in the target document.

The official message

Fragment identifier is not defined.

Default severity
Error. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.
EPUBCheck version
5.4.0

Typical causes

  • Footnote or table of contents links to an id that was renamed or never written, a common result of conversion and of splitting a book into chapters.
  • A link that targets the right id but the wrong file after a chapter was split.

How to fix it

  • Add the missing id to the target element, or correct the link to an id that exists.
  • After splitting chapters, update links so they name the file where the id now lives.

Terms used here

Other RSC messages

  • RSC-011 Found a reference to a resource that is not a spine item.
  • RSC-013 Fragment identifier is used in a reference to a stylesheet resource.
  • RSC-010 Reference to non-standard resource type found.
  • RSC-009 A non-SVG image resource should not be defined with a fragment identifier.
  • RSC-015 A fragment identifier is required for svg use tag references.
  • RSC-008 Referenced resource "…" is not declared in the OPF manifest.

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

FAQ

What does EPUBCheck RSC-012 mean?

EPUBCheck RSC-012 is an error message: “Fragment identifier is not defined.” A link points to a fragment (#id) that does not exist in the target document.

Is RSC-012 an error?

RSC-012 is reported as error by default. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.