After installation of SUPEE-10415 patch on, an error is shown after flushing the Magento cache:

There has been an error processing your request

Cannot send headers; headers already sent in /home/youngag/public_html/magento/app/code/core/Mage/Core/Model/Config.php, line 1245

#0 /home/youngag/public_html/magento/lib/Zend/Controller/Response/Abstract.php(115): Zend_Controller_Response_Abstract->canSendHeaders(true)
#1 /home/youngag/public_html/magento/app/code/core/Mage/Core/Model/App.php(1246): Zend_Controller_Response_Abstract->setHeader('Content-Type', 'text/html; char...')
#2 /home/youngag/public_html/magento/app/code/core/Mage/Core/Controller/Varien/Front.php(80): Mage_Core_Model_App->getResponse()
#3 /home/youngag/public_html/magento/app/code/core/Mage/Core/Model/Url/Rewrite.php(204): Mage_Core_Controller_Varien_Front->getResponse()
#4 /home/youngag/public_html/magento/app/code/core/Mage/Core/Controller/Varien/Front.php(166): Mage_Core_Model_Url_Rewrite->rewrite()
#5 /home/youngag/public_html/magento/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#6 /home/youngag/public_html/magento/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#7 /home/youngag/public_html/magento/index.php(93): Mage::run('', 'store')
#8 {main}

Has anyone else encountered this error? Any insight as to how to solve this issue would be appreciated.


1 Answer 1


check your excpetions log for the following message:

"exception 'Exception' with message 'Unsupported data type N' in /var/www/src/lib/Unserialize/Reader/ArrValue.php:88 Stack trace: .."

If you get this one, then most likely the Patch 8788v2 has not been applied. The files solving the issue are: /lib/Unserialize/Parser.php /lib/Unserialize/Reader/Arr.php /lib/Unserialize/Reader/ArrValue.php /lib/Unserialize/Reader/Null.php

Expcially if you are missing the /lib/Unserialize/Reader/Null.php file it means the patch has not been applied.

Greet axe

  • Thank you. I'm afraid that's not the issue however. The patch was previously applied and /lib/Unserialize/Reader/Null.php is in place.
    – jpluttme
    Commented Apr 20, 2018 at 17:16
  • Log files seem to indicate an issue with lib/Varien/Simplexml/Config.php, specifically: XML declaration allowed only at the start of the document on line 510 which is: $xml = simplexml_load_string($string, $this->_elementClass);
    – jpluttme
    Commented Apr 20, 2018 at 17:21
  • Does your page load when you clear your cache? And then it crashes when you reload?
    – axe1987
    Commented Apr 20, 2018 at 17:35
  • If this is the case then check all module XML files for valid XML. There can also be a faulty config entry in your core_config_data. Look for a key with a number like somekey/2/subkey
    – axe1987
    Commented Apr 20, 2018 at 17:43

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