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EPUBCheck · Package document (OPF)

OPF-040

Updated:

EPUBCheck OPF-040 is an error message: “Fallback item with id "…" could not be found.” A manifest item's fallback attribute names an id that no manifest item has.

The official message

Fallback item with id "%1$s" could not be found.

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

  • The fallback item was removed or its id renamed.

How to fix it

  • Point the fallback at an existing item id, or remove the fallback if the resource is a core media type and needs none.

Terms used here

Other OPF messages

  • OPF-043 Spine item with non-standard media-type "…" has no fallback.
  • OPF-035 Media type "text/html" is not appropriate for XHTML/OPS.
  • OPF-034 The spine contains multiple references to the manifest item with id "…".
  • OPF-033 The spine contains no linear resources.

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

FAQ

What does EPUBCheck OPF-040 mean?

EPUBCheck OPF-040 is an error message: “Fallback item with id "…" could not be found.” A manifest item's fallback attribute names an id that no manifest item has.

Is OPF-040 an error?

OPF-040 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.