octobercms/october · error · SystemException

A widget class name ':name' has not been registered

Error message

A widget class name ':name' has not been registered

What it means

Error "A widget class name ':name' has not been registered" thrown in octobercms/october.

Source

Thrown at modules/backend/widgets/form/HasFormWidgets.php:72

                return $field->getOptionsFromModel($this->model, $fieldOptions, $this->data);
            });
        }

        // Create form widget instance
        $widgetConfig = $this->makeConfig($field->config);
        $widgetConfig->alias = $this->alias . studly_case($this->nameToId($field->fieldName));
        $widgetConfig->sessionKey = $this->getSessionKey();
        $widgetConfig->sessionKeySuffix = $this->sessionKeySuffix;
        $widgetConfig->previewMode = $this->previewMode;
        $widgetConfig->model = $this->model;
        $widgetConfig->data = $this->data;
        $widgetConfig->parentForm = $this;

        $widgetName = $widgetConfig->widget;
        $widgetClass = $this->widgetManager->resolveFormWidget($widgetName);

        if (!class_exists($widgetClass)) {
            throw new SystemException(Lang::get(
                'backend::lang.widget.not_registered',
                ['name' => $widgetClass]
            ));
        }

        $widget = $this->makeFormWidget($widgetClass, $field, $widgetConfig);

        return $this->formWidgets[$field->fieldName] = $widget;
    }

    /**
     * isFormWidget checks if a field type is a widget or not
     */
    protected function isFormWidget(string $fieldType): bool
    {
        if (!$fieldType) {
            return false;
        }

View on GitHub (pinned to b608633a7e)

When it happens

Trigger: Thrown at modules/backend/widgets/form/HasFormWidgets.php:72 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/b0ab31e630fc238e. Report an issue: GitHub.