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HTM-001Critical Ingestion Error

Any publication resource that is an XML-based media type must be a ...

Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: resource.

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PreFlight checks for HTM-001 issues in memory and provides 1-click remediation during client-side packaging.

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What This Error Means in Plain English

EPUBCheck detected Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: resource.. Digital reading systems and bookstores require standard conformance to ensure compatibility across all reading apps.

Why Retailers & EAA Regulations Block This File

Automated book distributors (Apple Books, Amazon KDP, Kobo, and IngramSpark) run strict EPUBCheck validation on ingest and reject non-compliant files.

Technical Specification: W3C EPUBCheck rule HTM-001: Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: resource.

Manual Fix Instructions (for Sigil / Calibre)

  1. Locate the file and line flagged under rule HTM-001 in your EPUB editor (Sigil or Calibre).
  2. Apply the required syntax correction matching the HTM-001 specification.
  3. Re-pack and validate with PreFlight EPUB to confirm zero residual errors.