Cart Empty in checkout Issues in magento

Cart Empty in checkout Issues

Shopping cart is empty magento

System->Configuration->WEB->Cookie Session.

Set Cookie Lifetime to: 86400

Url : http://www.blog.plazathemes.com/archives/2104

Mage_PageCache - External full page cache

system->config->system->External Full Page Cache Setting

Session Lifetime (seconds) : 3600

Url : http://magento.stackexchange.com/questions/29513/mage-pagecache-external-full-page-cache

Security

System > Configuration > Admin > Security

Session Lifetime (seconds) : 14400

Url : http://www.magbooster.com/change-magento-session-timeout/

Turn “Validate HTTP_USER_AGENT” to yes (see screenshot) and refresh cache.

System->Configuration->WEB-> Session validation setting

Validate HTTP_USER_AGENT : yes

magento\app\code\core\Mage\Core\Model\Session\Abstract\Varien.php

$cookieParams = array(
‘lifetime’ => $cookie->getLifetime(),
‘path’ => $cookie->getPath(),
‘domain’ => $cookie->getConfigDomain(),
‘secure’ => $cookie->isSecure(),
‘httponly’ => $cookie->getHttponly()
);

change to

$cookieParams = array(
‘lifetime’ => $cookie->getLifetime(),
‘path’ => $cookie->getPath()
);