Skip to content
EPUBCheck · Package document (OPF)

EPUBCheck OPF-018: unneeded remote-resources

Updated:

EPUBCheck OPF-018 is a warning message: “The "remote-resources" property was declared in the Package Document, but no reference to remote resources has been found.” A manifest item declares remote-resources, but EPUBCheck found no reference to a remote resource in it. The property tells reading apps that the document needs the network, so it should only be there when it is true.

The official message

The "remote-resources" property was declared in the Package Document, but no reference to remote resources has been found.

Default severity
Warning. The EPUB is still valid, but something is likely to cause problems in some reading apps. EPUBCheck exits with 0 unless you pass --failonwarnings.
EPUBCheck version
5.4.0

Typical causes

  • The remote image, font, audio or video was removed or copied into the EPUB, but the property stayed.
  • A template manifest that declared remote-resources on every document.
  • A tool that adds the property by default.

How to fix it

  1. Find the manifest item EPUBCheck points to.
  2. Confirm the document no longer loads anything from an http or https address.
  3. Remove remote-resources from that item's properties attribute, keeping any other properties.

When it's not this

If the document uses scripts, EPUBCheck reports OPF-018b instead, because a script could load the resource.

Terms used here

Other OPF messages

  • OPF-018b The "remote-resources" property was declared in the Package Document, but no reference to remote resources has been found; please check scripted content to make sure the property is legit.
  • OPF-017 The attribute "full-path" on element "rootfile" must not be empty.
  • OPF-016 The element "rootfile" is missing its required attribute "full-path".
  • OPF-015 The property "…" should not be declared in the OPF file.
  • OPF-021 Use of non-registered URI scheme type in href: "…".
  • OPF-014 The property "…" should be declared in the OPF file.

Sources

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

FAQ

What does EPUBCheck OPF-018 mean?

EPUBCheck OPF-018 is a warning message: “The "remote-resources" property was declared in the Package Document, but no reference to remote resources has been found.” A manifest item declares remote-resources, but EPUBCheck found no reference to a remote resource in it. The property tells reading apps that the document needs the network, so it should only be there when it is true.

Is OPF-018 an error?

OPF-018 is reported as warning by default. The EPUB is still valid, but something is likely to cause problems in some reading apps. EPUBCheck exits with 0 unless you pass --failonwarnings.