Free private lookup

Explain an EPUBCheck error

Paste a validator code or its full message. The lookup runs locally and points you to the broken package layer, the likely cause and a safe repair order.

EPUB repair flow checking container, manifest, spine, resources, XHTML and CSS. — Repair upstream structure before downstream formatting. One missing path can create many later messages.

Message lookup

Paste the exact error

Examples include PKG-006, RSC-005, OPF-049, HTM-046, or a plain-language message.

How to use the result

Fix the first real cause

Keep the code

The stable EPUBCheck code is more useful than a shortened message copied from another app.

Open the named file

Use the reported path, line and column. Check exact case because EPUB references are case-sensitive.

Rebuild and recheck

Validate the newly packaged EPUB. Fixing an upstream path or XML error can remove several downstream messages.

Need the full repair sequence?

Use the validation-error guide to triage fatal errors, errors and warnings without chasing symptoms.

Fix EPUB validation errors →