octobercms/october · error · Exception

Component not found

Error message

Component not found

What it means

While building component metadata for the CMS Editor (EditorExtension), makeTemplateComponent() asks ComponentManager to instantiate a component by name; if makeComponent returns null (unregistered component, disabled or missing plugin) it throws a plain 'Component not found' Exception. Unlike front-end rendering there is no strict-mode opt-out here.

Source

Thrown at modules/cms/classes/editorextension/HasComponentListLoader.php:103

    /**
     * makePropertiesForUnknownComponent
     */
    private function makePropertiesForUnknownComponent($properties, $alias)
    {
        $properties['oc.alias'] = $alias;

        return $properties;
    }

    /**
     * makeTemplateComponent
     */
    private function makeTemplateComponent($manager, $name, $properties, $alias)
    {
        $componentObj = $manager->makeComponent($name, null, $properties);
        if (!$componentObj) {
            throw new Exception('Component not found');
        }

        $componentObj->alias = $alias;

        $propertyConfig = ComponentHelpers::getComponentsPropertyConfig($componentObj, true, true);
        $propertyConfig = json_encode($propertyConfig, JSON_UNESCAPED_SLASHES);

        $propertyValues = ComponentHelpers::getComponentPropertyValues($componentObj, true);
        $propertyValues = json_encode($propertyValues, JSON_UNESCAPED_SLASHES);

        return [
            'alias' => $alias,
            'name' => $componentObj->name,
            'title' => ComponentHelpers::getComponentName($componentObj),
            'icon' => $this->getComponentPluginIcon($manager, $componentObj),
            'className' => get_class($componentObj),
            'description' => ComponentHelpers::getComponentDescription($componentObj),
            'inspectorEnabled' => $componentObj->inspectorEnabled,

View on GitHub (pinned to b608633a7e)

Solutions

1. Re-enable or reinstall the plugin that registers the component
2. Remove the stale component reference from the saved template (edit the file or database record directly)
3. Clear CMS/config caches so the editor rebuilds its component list
4. If you renamed the component, keep the old name registered as an alias in registerComponents()

Example fix

// before: component class no longer registered
public function registerComponents(): array { return []; }

// after
public function registerComponents(): array
{
    return [\My\Plugin\Components\Alert::class => 'alert'];
}

use \Cms\Classes\ComponentManager;
$manager = ComponentManager::instance();
foreach ($templateComponentNames as $name) {
    if (!$manager->hasComponent($name)) {
        unset($components[$name]); // drop unresolvable entries before editor payloads are built
    }
}

When it happens

Trigger: The editor loads a saved template whose settings still reference a component from a disabled/uninstalled plugin, or the component list loader is asked to expand an unknown component name while building the template listing.

Common situations: Disabling a plugin but leaving its components in saved pages/partials; renaming a component class without updating stored references; cached editor payloads from an older Winter version.

Related errors

• cms::lang.component.no_records
• cms::lang.component.not_found
• Component does use a default partial
• cms::lang.component.not_found
• Document data is not provided

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/7addd59f6cfd5d75. Report an issue: GitHub.