Blank admin screen after upgrade from 1.7 to 1.9.2.4 via Magento Connect

Question

I chose to upgrade via magento connect and am now getting a blank screen for admin with an error when printed of

Fatal error: Class 'Unserialize_Parser' not found in /var/www/web/app/code/core/Mage/Core/Helper/UnserializeArray.php on line 43

I've cleared cache and session folders, is it related to certain patches? how can i troubleshoot/resolve please?

Answer 1

Checking given file /var/www/web/app/code/core/Mage/Core/Helper/UnserializeArray.php on line 43

class Mage_Core_Helper_UnserializeArray
{
    public function unserialize($str)
    {
        $parser = new Unserialize_Parser();
        return $parser->unserialize($str);
    }
}

Check in lib folder have no directory Unserialize so it trigger error.

Download fresh magento and upload it to lib folder.

Answer 2

I have worked on this issue few days back. Unistall the local.xml and then re-install magento 1.9. It worked for me. Let me know your response.