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EPUBCheck · Package document (OPF)

EPUBCheck OPF-060: duplicate file names in ZIP

Updated:

EPUBCheck OPF-060 is an error message: “Duplicate entry in the ZIP file: "…" (file names must be unique after Unicode canonical normalization and full case folding).” Two files in the ZIP have names that are the same once case and Unicode normalisation are ignored, such as Image.jpg and image.jpg. EPUB requires file names to stay unique under those rules.

The official message

Duplicate entry in the ZIP file: "%1$s" (file names must be unique after Unicode canonical normalization and full case folding).

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

  • Files added on a case-sensitive system that a case-insensitive one would treat as the same file.
  • The same file added twice under different spellings, for example with composed and decomposed accents.
  • Two versions of an image kept side by side after editing.

How to fix it

  1. Read the file name EPUBCheck quotes.
  2. Rename or delete one of the two files.
  3. After renaming, update every reference to the file: the manifest in the package document, links and image sources in the XHTML, and url() references in the CSS.

When it's not this

If the same file is declared twice in the manifest, that is OPF-074.

Terms used here

Other OPF messages

  • OPF-062 Found Adobe page-map attribute on spine element in opf file.
  • OPF-063 Referenced Adobe page-map item "…" was not found in the manifest.
  • OPF-055 … tag is empty.
  • OPF-065 Invalid metadata declaration, probably due to a cycle in "refines" metadata.
  • OPF-054 Date value "…" is not valid as per http://www.w3.org/TR/NOTE-datetime:….
  • OPF-066 Missing "dc:source" or "source-of" pagination metadata. The pagination source must be identified using the "dc:source" and "source-of" properties when the content includes page break markers.

Sources

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

FAQ

What does EPUBCheck OPF-060 mean?

EPUBCheck OPF-060 is an error message: “Duplicate entry in the ZIP file: "…" (file names must be unique after Unicode canonical normalization and full case folding).” Two files in the ZIP have names that are the same once case and Unicode normalisation are ignored, such as Image.jpg and image.jpg. EPUB requires file names to stay unique under those rules.

Is OPF-060 an error?

OPF-060 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.