When I mark an article as featured (view the article on the main page), so instead of home page shows a 404 error - JHTML icon not found. In the template, it is SJ Tech i have hide component - no.

Now I see, that i have answer from few month ago

Please go to ........\templates\sj_tech\html\com_content\featured\default.php and find:

defined('_JEXEC') or die;
if(!defined('YT_FRAMEWORK')){
throw new Exception(JText::_('INSTALL_YT_PLUGIN'));
}

=> Edit to:

defined('_JEXEC') or die;
if(!defined('YT_FRAMEWORK')){
throw new Exception(JText::_('INSTALL_YT_PLUGIN'));
}
if (!defined('DS')) {
define('DS', DIRECTORY_SEPARATOR);
}

Thanks