Empty page after updating Joomla 2.5.x to 3.2.x

Problem: You wish to update your Joomla 2.5.x (e.g. 2.5.17) to 3.2.x (e.g. 3.2.1). But after you upgraded Joomla (e.g. via the upgrade option in Joomla or via extracting the latest Joomla version over the existing one) you lost access to your side and the frontend and the backend show only a white screen.

Solution: We where able to solve the issue mentioned above via the following steps:

1. Try to open the following URL http://<your website>/administrator/index.php?option=com_installer&view=database
2. If you got a white screen rename the libraries folder in your joomla installation and upload a fresh an new one from the latest joomla installation files
3. You might get now a SQL error message. To solve that you need to run the following SQL syntax (you need to replace with your current one):

   CREATE TABLE IF NOT EXISTS `_content_types` (
     `type_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
     `type_title` varchar(255) NOT NULL DEFAULT '',
     `type_alias` varchar(255) NOT NULL DEFAULT '',
     `table` varchar(255) NOT NULL DEFAULT '',
     `rules` text NOT NULL,
     `field_mappings` text NOT NULL,
     `router` varchar(255) NOT NULL  DEFAULT '',
     `content_history_options` varchar(5120) COMMENT 'JSON string for com_contenthistory options',
     PRIMARY KEY (`type_id`),
     KEY `idx_alias` (`type_alias`)
   ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=10000;

4. After that please try again the url http://<your website>/administrator/index.php?option=com_installer&view=database
5. You should see a fix button now. Press on it to fix the DB structure.
6. Once the structure is fixed you might need to select the correct admin template, as “Bluestork – Default” isn´t any longer working.
7. To do that click on “Extension” -> “Extension Manager” -> “Discover”
8. As location select Administration and as type template then press discover
9. Select both templates in the list (hathor and ISIS) and press install
10. Now click on “extensions” -> “template manager”
11. select isis and press on default