Modified Jomsocial registration file to send notification emails to all users with (Recieve System Emails) active. File location ROOT/components/com_community/controllers

PROFILE_default.php

//go to components/com_users/views/profile/tmpl/default.php

//add after the comments

#Start never show Joomla default profile page
  $app = &JFactory::getApplication();
  $app->redirect(JURI::base()."path-to-jomsocial-menu-item/my-profile-page");
#Stop never show Joomla default profile page

register.php

  	if($type == 'registration_complete')
		{
			//Send notification email to administrators (Recieve system emails)
				
				// get all users who are set to recieve system emails
				$db       = JFactory::getDBO();
				$querySendMailRecipients = 'SELECT name, email, sendEmail, id' .
							' FROM #__users' .
							' WHERE sendEmail=1';
	
				$db->setQuery( $querySendMailRecipients );
				$SendMailRecipientsrows = $db->loadAssocList();
				
				foreach ($SendMailRecipientsrows as $SendMailRrows => $SendMailRrow )
				{
					if ($requireApproval)
					{
						$message2 = JText::sprintf( JText::_( 'COM_COMMUNITY_USER_REGISTERED_NEEDS_APPROVAL' ), $SendMailRrow['name'], $sitename, $name, $email, $username);
					}
					else
					{
						$message2 = JText::sprintf( JText::_( 'COM_COMMUNITY_SEND_MSG_ADMIN' ), $SendMailRrow['name'], $sitename, $name, $email, $username);
					}

					$message2 = html_entity_decode($message2, ENT_QUOTES);

					//check if HTML emails are set to ON
					if ($config->get('htmlemail'))
					{
						$sendashtml = true;
						$tmpl       = new CTemplate();
						$message2   = CString::str_ireplace(array("\r\n", "\r", "\n"), '<br />', $message2);

						$tmpl->set('name', $SendMailRrow['name']);
						$tmpl->set('email', $SendMailRrow['email']);

						$message2 = $tmpl->set('unsubscribeLink', CRoute::getExternalURL('index.php?option=com_community&view=profile&task=privacy'), false)
									->set('content', $message2)
									->set('copyrightemail', $copyrightemail)
									->set('sitename', $config->get('sitename'))
									->fetch('email.html');
					}
					$mail = JFactory::getMailer();
					$mail->sendMail($mailfrom, $fromname, $SendMailRrow['email'], $subject, $message2, $sendashtml);
				}
		}

REGISTER_default.php

//go to components/com_users/views/registration/tmpl/default.php

//add after the comments

#Start never use joomla registration form
  $app = &JFactory::getApplication();
  $app->redirect(JURI::base()."path-to-jomsocial-menu-item/register");
#Stop never use joomla registration form

register_OLD.php

  	if($type == 'registration_complete' && ( !$requireApproval ))
		{
			//Send notification email to administrators
			foreach ($rows as $row)
			{
				if ($row->sendEmail)
				{
					if ($requireApproval)
					{
						$message2 = JText::sprintf( JText::_( 'COM_COMMUNITY_USER_REGISTERED_NEEDS_APPROVAL' ), $row->name, $sitename, $name, $email, $username);
					}
					else
					{
						$message2 = JText::sprintf( JText::_( 'COM_COMMUNITY_SEND_MSG_ADMIN' ), $row->name, $sitename, $name, $email, $username);
					}

					$message2 = html_entity_decode($message2, ENT_QUOTES);

					//check if HTML emails are set to ON
					if ($config->get('htmlemail'))
					{
						$sendashtml = true;
						$tmpl       = new CTemplate();
						$message2   = CString::str_ireplace(array("\r\n", "\r", "\n"), '<br />', $message2);

						$tmpl->set('name', $name);
						$tmpl->set('email', $row->email);

						$message2 = $tmpl->set('unsubscribeLink', CRoute::getExternalURL('index.php?option=com_community&view=profile&task=privacy'), false)
									->set('content', $message2)
									->set('copyrightemail', $copyrightemail)
									->set('sitename', $config->get('sitename'))
									->fetch('email.html');
					}
					$mail = JFactory::getMailer();
					$mail->sendMail($mailfrom, $fromname, $row->email, $subject, $message2, $sendashtml);
				}
			}
		}