EPUB error guide

RSC-007 EPUB error

How to understand and scan RSC_007 EPUB errors caused by broken internal references.

Error text

RSC_007: Referenced resource could not be found in the EPUB.

When you usually see it

EPUBCheck reports RSC_007 during validation, often after an export, rename, or manual edit inside the EPUB package.

Plain English

What it means inside the EPUB.

RSC_007 means the EPUB contains an internal pointer to something that cannot be resolved.

The broken pointer can live in XHTML href or src attributes, CSS url() values, OPF manifest references, nav links, or NCX content sources.

User checklist

What to inspect before another upload.

These checks keep the repair decision tied to the EPUB package instead of guessing from a generic error code.

Find the source file that contains the broken href, src, CSS url(), nav entry, NCX entry, or manifest reference.
Compare the referenced path with the real ZIP entry path inside the EPUB, including folder and letter case.
Do not guess a replacement if several similarly named files could be the intended target.

Standards context

Why this error matters to validators.

EPUBCheck

EPUBCheck evaluates EPUB 2 and EPUB 3 publications against official EPUB specifications and reports structure, package, markup, and reference problems.

EPUB 3.3 package document

The package document defines the metadata, manifest, spine, and navigation wiring that validators inspect before a reading system can process the book reliably.

Repairability

Can EPUB Fixer repair it?

Safe repair condition

Safe repairs include fixing obvious path case differences, URL encoding mismatches, relative path mistakes, or missing manifest declarations.

When it stops at diagnosis

The repair is not deterministic when several files could match, or when the referenced resource is absent from the EPUB.

Before / after example

Before: a nav entry points to text/chapter-03.xhtml, but the package contains Text/chapter-03.xhtml. After: the nav link uses the packaged path.

Next step

Scan the actual file before editing by hand.

The same error code can come from different files and different causes. Uploading the EPUB lets the report show the affected path and whether the fix is deterministic.

Upload EPUB to scan

FAQ

Common questions about this EPUB error.

What does RSC-007 mean in EPUBCheck?

RSC_007 means an internal EPUB reference points to a file that EPUBCheck cannot resolve. It often appears in links, image sources, CSS URLs, OPF manifest items, nav files, or NCX entries.

How do I find the broken file behind an RSC-007 error?

Use the path in the EPUBCheck or KDP message as the starting point, then inspect the packaged EPUB files for the closest real match. Case changes, folder moves, and URL encoding differences are common causes.

Can I fix RSC-007 without re-exporting the EPUB?

Sometimes. If the EPUB package already contains the intended file, a targeted path or manifest correction may be enough. If the file is missing, re-exporting or restoring the source file is usually required.

Will Kindle Previewer show the same RSC-007 problem?

Kindle Previewer can report the same underlying broken reference, but the wording may differ from EPUBCheck. The important detail is the affected path and whether the referenced file exists in the EPUB.