Back to Error DirectoryW3C EPUBCheck Standard
CHK-004Retailer Warning

The custom message contains too many parameters in message override...

The custom message contains too many parameters in message overrides file "resource".

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What This Error Means in Plain English

EPUBCheck detected The custom message contains too many parameters in message overrides file "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 CHK-004: The custom message contains too many parameters in message overrides file "resource".

Manual Fix Instructions (for Sigil / Calibre)

  1. Locate the file and line flagged under rule CHK-004 in your EPUB editor (Sigil or Calibre).
  2. Apply the required syntax correction matching the CHK-004 specification.
  3. Re-pack and validate with PreFlight EPUB to confirm zero residual errors.