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EPUBCheck · Resources and references

EPUBCheck RSC-006: remote resource not allowed

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EPUBCheck RSC-006 is an error message: “Remote resource reference is not allowed in this context; resource "…" must be located in the EPUB container.” A resource is loaded from the web in a place where EPUB requires it to be inside the EPUB file. Only audio, video, fonts and resources fetched by scripts may stay remote; everything else must be in the container so the book works offline.

The official message

Remote resource reference is not allowed in this context; resource "%1$s" must be located in the EPUB container.

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

%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.

Typical causes

  • Images or stylesheets referenced by an http or https URL instead of a file in the book.
  • Content copied from a web page with its absolute image URLs.

How to fix it

  1. Download the resource, add it to the EPUB and the manifest, and reference it by a relative path.
  2. EPUB 3 allows remote audio, video and fonts; those need the remote-resources property on the manifest item of the document that uses them.
  3. Validate again.

When it's not this

An ordinary hyperlink to a website is allowed; RSC-006 is about resources the page loads, such as images.

Terms used here

Other RSC messages

  • RSC-006b Resource "…" is located outside the EPUB Container; please check the resource is retrieved in scripted content.
  • RSC-005 Error while parsing file: …
  • RSC-007 Referenced resource "…" could not be found in the EPUB.
  • RSC-004 File "…" is encrypted, its content will not be checked.
  • RSC-008 Referenced resource "…" is not declared in the OPF manifest.
  • RSC-003 No rootfile tag with media type "application/oebps-package+xml" was found in the container.

Sources

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

FAQ

What does EPUBCheck RSC-006 mean?

EPUBCheck RSC-006 is an error message: “Remote resource reference is not allowed in this context; resource "…" must be located in the EPUB container.” A resource is loaded from the web in a place where EPUB requires it to be inside the EPUB file. Only audio, video, fonts and resources fetched by scripts may stay remote; everything else must be in the container so the book works offline.

Is RSC-006 an error?

RSC-006 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.