Magento Admin panel login not working in localhost

Step 1: Copy varien.php file from app\code\core\Mage\Core\Model\Session\Abstract folder

Step 2: Paste into app\code\local\Mage\Core\Model\Session\Abstract folder. Before you paste the file you need to create the folders as specified in this path such as \Mage\Core\Model\Session\Abstract.

Step3: Open varien.php in your favorite editor.

Step4: Find line no 96 and the code will be like

if (isset($cookieParams['domain'])) {

$cookieParams['domain'] = $cookie->getDomain();

}

     and replace with

if ((isset($cookieParams['domain'])) && !in_array("127.0.0.1", self::getValidatorData())) {

$cookieParams['domain'] = $cookie->getDomain();

}

Step 5: That’s it. Now you will be able to login Magento admin panel.

Magento Admin panel login not working in Chrome

Go to /app/code/core/Mage/Core/Model/Session/Abstract/Varien.php

Find line no 85 and the code will be like

       // session cookie params

       $cookieParams = array(

           'lifetime' => $cookie->getLifetime(),

           'path'     => $cookie->getPath(),

           'domain'   => $cookie->getConfigDomain(),

           'secure'   => $cookie->isSecure(),

           'httponly' => $cookie->getHttponly()

       );

and replace with  

       $cookieParams = array(

           'lifetime' => $cookie->getLifetime(),

           'path'     => $cookie->getPath(),

           'domain'   => $cookie->getConfigDomain(),

           'secure'   => $cookie->isSecure(),

         //  'httponly' => $cookie->getHttponly()

       );

That’s it. Now you will be able to login Magento admin panel.