I\'ve recently upgraded to Magento CE 1.9.1.0 and our order confirmation emails are not being sent to customers or the employees here that are setup to receive notifications
Goto /app/code/core/Mage/Core/Model/Email/Template.php
Below changes :
if ($this->hasQueue() && $this->getQueue() instanceof Mage_Core_Model_Email_Queue) {
To
if (false){