Magento 1.9.0.1 - SUPEE 5994 not applied

[Shubham S]

Hi,

I am using magento 1.9.0.1 CE and when I am trying to apply SUPEE-5994 patch , it is throwing below error : 

Checking if patch can be applied/reverted successfully...
ERROR: Patch can't be applied/reverted successfully.

patching file app/code/core/Mage/Authorizenet/controllers/Directpost/PaymentController.php
patching file app/code/core/Mage/Core/Controller/Varien/Router/Admin.php
patching file app/code/core/Mage/Core/Controller/Varien/Router/Standard.php
patching file app/code/core/Mage/Customer/Model/Customer.php
Hunk #1 FAILED at 273.
1 out of 1 hunk FAILED -- saving rejects to file app/code/core/Mage/Customer/Model/Customer.php.rej
patching file app/code/core/Mage/Dataflow/Model/Convert/Parser/Csv.php
patching file app/code/core/Mage/ImportExport/Model/Export/Adapter/Csv.php
patching file app/code/core/Mage/Install/Controller/Router/Install.php
patching file app/code/core/Mage/Install/etc/config.xml
patching file app/code/core/Mage/Sales/controllers/Recurring/ProfileController.php
patching file downloader/Maged/Model/Connect.php
patching file downloader/Maged/View.php
patching file downloader/template/connect/packages_prepare.phtml
patching file downloader/template/messages.phtml
patching file get.php
patching file lib/PEAR/PEAR/PEAR.php
patching file lib/PEAR/PEAR/PEAR5.php
patching file lib/Varien/Io/File.php

How to resolve this?

[Gabriel Guarino]

Hi @Shubham S,

First things first. Has the Magento core been modified in your Magento instance?

Best regards.

Gabriel