“Validating h5p package failed. Missing required library”: what it means

You upload a .h5p file to Moodle, WordPress or Drupal and get:

Validating h5p package failed. Missing required library H5P.Timer 0.4

It means the site needs a piece of code the content depends on, and it can’t find it either in the file you uploaded or among the libraries already installed on the site. There are two ways that happens, and the fix depends on which one you have.

If the missing library is the file’s main content type, the message says “Missing main library” instead; the causes are the same.

What a library is

Every H5P content type (Interactive Video, Course Presentation, Drag and Drop and so on) is built from libraries: small bundles of code with a name and a version, such as H5P.InteractiveVideo 1.26. A .h5p file lists the libraries it needs in a file called h5p.json, and it usually carries copies of them in its own folders. When you upload it, the site installs any bundled libraries it doesn’t have yet, if your account is allowed to.

Cause 1: the site won’t install the library from your file

The library is in the file, but the site doesn’t let you add it. If your account isn’t allowed to install libraries, H5P ignores the ones in your file and reports them as missing. It then adds: “Note that the libraries may exist in the file you uploaded, but you’re not allowed to upload new libraries. Contact the site administrator about this.” By default, Moodle lets only managers and administrators install H5P content types, and the H5P plugin for WordPress lets only administrators manage libraries.

A newer library can also need newer H5P core files than the site runs. H5P then also says the component “requires a newer version of the H5P plugin” (listed as “API version unsupported” on H5P’s troubleshooting page).

Fix: ask your site administrator to install or update that content type (Moodle’s built-in H5P: Site administration → H5P → Manage H5P content types; the Interactive Content (mod_hvp) plugin: Site administration → Plugins → Activity modules → Interactive Content → Libraries, which needs the mod/hvp:updatelibraries capability), or to upload the file for you. If you are the administrator, upload it yourself: your account can install the libraries it carries. If H5P says the site needs a newer H5P plugin, update the plugin (or Moodle) first.

Cause 2: the library isn’t in the file at all

A file can list a library in h5p.json that none of its folders contain, for example after it was repackaged or edited by hand. A file can also bundle a different version from the one it asks for, for example 1.25 when h5p.json needs 1.26. Then no amount of permission on the site will help unless the site already has the exact version.

Fix: export the content again from the tool that made it, or get the site to install the missing version first.

How to tell which one you have

Open the .h5p file as a zip archive (rename it to .zip if needed). Look in h5p.json under preloadedDependencies, then check that there is a folder for each library, named like H5P.Timer-0.4, with a library.json inside whose version matches.

The folder is there with the right version → it’s the site (cause 1).
The folder is missing, or has another version → it’s the file (cause 2).

That’s quick for one library, but most content types depend on many, and each library can need others.

Check it automatically

Our H5P Package Checker does this for you. Give it links to one or more .h5p files and for each one you get a report that lists:

every library the content needs that isn’t in the file (so the site must already have it),
every library bundled in a different version from the one required,
an h5p.json that is missing, invalid or not at the top of the zip, which happens when a package is zipped from its parent folder,
file types H5P won’t accept, and other problems from the published H5P file specification, each with its source.

If the report shows every required library is bundled at the right version, the missing-library error isn’t coming from the file, and the fix is on the site.

It runs on the Apify platform and takes file links, not uploads, so the files need to be reachable by a link. It checks the file against the published H5P specification; it can’t see what your site has installed, so it can’t promise an upload will succeed.

Check an H5P file →

H5P is a registered trademark of H5P Group; Madrasco is not affiliated with or endorsed by H5P Group.

Last updated 26 September 2026. Something wrong or out of date? [email protected]