How do I fix this error- Element 'reference': This element is not expected

Question

I am on Magento 2.2.3. I tried to install the Ultimo theme and got this error. I realized it would not work for me. I went ahead and removed the theme and now receive this-

1 exception(s):
Exception #0 (Magento\Framework\Config\Dom\ValidationException): Element 'reference': This element is not expected.
Line: 1


Exception #0 (Magento\Framework\Config\Dom\ValidationException): Element 'reference': This element is not expected.
Line: 1

#0 /var/www/html/vendor/magento/framework/Config/Dom.php(115): Magento\Framework\Config\Dom->_initDom('<layout xmlns:x...')
#1 /var/www/html/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php(111): Magento\Framework\Config\Dom->__construct('<layout xmlns:x...', Object(Magento\Framework\App\Arguments\ValidationState), Array, NULL, '/var/www/html/w...', '%message%\nLine:...')
#2 /var/www/html/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(66): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject('Magento\\Framewo...', Array)
#3 /var/www/html/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create('Magento\\Framewo...', Array)
#4 /var/www/html/vendor/magento/framework/Config/DomFactory.php(42): Magento\Framework\ObjectManager\ObjectManager->create('Magento\\Framewo...', Array)
#5 /var/www/html/vendor/magento/framework/View/Model/Layout/Update/Validator.php(141): Magento\Framework\Config\DomFactory->createDom(Array)
#6 /var/www/html/vendor/magento/framework/View/Model/Layout/Merge.php(461): Magento\Framework\View\Model\Layout\Update\Validator->isValid('<layout xmlns:x...', 'layout_merged', false)
#7 /var/www/html/vendor/magento/framework/View/Model/Layout/Merge.php(442): Magento\Framework\View\Model\Layout\Merge->_validateMergedLayout('LAYOUT_frontend...', '<reference name...')
#8 /var/www/html/generated/code/Magento/Framework/View/Model/Layout/Merge/Interceptor.php(193): Magento\Framework\View\Model\Layout\Merge->load(Array)
#9 /var/www/html/vendor/magento/framework/View/Layout/Builder.php(86): Magento\Framework\View\Model\Layout\Merge\Interceptor->load()
#10 /var/www/html/vendor/magento/framework/View/Layout/Builder.php(63): Magento\Framework\View\Layout\Builder->loadLayoutUpdates()
#11 /var/www/html/vendor/magento/framework/View/Layout.php(254): Magento\Framework\View\Layout\Builder->build()
#12 /var/www/html/vendor/magento/framework/View/Layout.php(875): Magento\Framework\View\Layout->build()
#13 /var/www/html/generated/code/Magento/Framework/View/Layout/Interceptor.php(414): Magento\Framework\View\Layout->getBlock('page_content_he...')
#14 /var/www/html/vendor/magento/module-cms/Helper/Page.php(171): Magento\Framework\View\Layout\Interceptor->getBlock('page_content_he...')
#15 /var/www/html/vendor/magento/module-cms/Controller/Index/Index.php(43): Magento\Cms\Helper\Page->prepareResultPage(Object(Magento\Cms\Controller\Index\Index\Interceptor), 'new-home')
#16 /var/www/html/generated/code/Magento/Cms/Controller/Index/Index/Interceptor.php(24): Magento\Cms\Controller\Index\Index->execute(NULL)
#17 /var/www/html/vendor/magento/framework/App/Action/Action.php(107): Magento\Cms\Controller\Index\Index\Interceptor->execute()
#18 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http))
#19 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Cms\Controller\Index\Index\Interceptor->___callParent('dispatch', Array)
#20 /var/www/html/vendor/magento/module-customer-segment/Model/App/Action/ContextPlugin.php(81): Magento\Cms\Controller\Index\Index\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))

I only receive it in developer mode, in production mode everything works fine. This is the issue- https://github.com/magento/magento2/issues/11194#issuecomment-333978626 what I can't find is where the 'reference' is. How do I locate it?

Answer 1

This error indicates that somewhere in your XML layout files you have element <reference/>, which is not allowed. You can search for all occurrences of '<reference ' in your /app folder (*.xml).

If you can't find it, then it is possible that you have entered <reference> element in admin in XML Layout update field somewhere (Category, CMS Page, etc.), in this case you'll only get error on that page / category. If you have error on Home page, check 'Layout Update XML' field for Page with 'home' URL key.

Answer 2

After removed the Ultimo theme you need to run the below ssh commands in your magento root directory:

rm -rf var/*
rm -rf pub/static/*
php bin/magento setup:upgrade
php bin/magento setup:static-content:deploy
chmod -R 777 var pub/static
php bin/magento cache:flush

I hope it will work.