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EPUBCheck · Resources and references

EPUBCheck RSC-010: link to a non-content file

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EPUBCheck RSC-010 is an error message: “Reference to non-standard resource type found.” A hyperlink points to a file that is not a document a reading app can display, such as a plain image or another non-content file inside the EPUB. Links must lead to content documents (XHTML or SVG).

The official message

Reference to non-standard resource type found.

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

  • A link to an image file instead of to the page that shows it.
  • A link to an embedded file such as a PDF or text file.
  • Image links kept from a web page (click to enlarge).

How to fix it

  1. Point the link at an XHTML document that contains the image or content.
  2. Or remove the link if readers cannot open the target anyway.
  3. Validate again.

When it's not this

If the target is a content document that is not in the spine, the error is RSC-011.

Terms used here

Other RSC messages

  • RSC-009 A non-SVG image resource should not be defined with a fragment identifier.
  • RSC-011 Found a reference to a resource that is not a spine item.
  • RSC-008 Referenced resource "…" is not declared in the OPF manifest.
  • RSC-012 Fragment identifier is not defined.
  • RSC-007 Referenced resource "…" could not be found in the EPUB.
  • RSC-013 Fragment identifier is used in a reference to a stylesheet resource.

Sources

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

FAQ

What does EPUBCheck RSC-010 mean?

EPUBCheck RSC-010 is an error message: “Reference to non-standard resource type found.” A hyperlink points to a file that is not a document a reading app can display, such as a plain image or another non-content file inside the EPUB. Links must lead to content documents (XHTML or SVG).

Is RSC-010 an error?

RSC-010 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.