This article is for those who experience the problem that Magento shows only a white/blank page in the Frontend, Backend or Magento Connect Manager. This problem is caused by a PHP fatal error in your Magento store.
Make the Error that causes the problem visible.
To solve the actual problem, it is necessary to locate where the problem originates from. To do this, we need to let Magento show the error instead of the white screen. You can do this by following different solutions.
First, you need to download and upload or edit the index.php file with your ftp client and insert the following code into the file.
Solution 1 : Disable Compiler
Go to System -> Tools -> Compilation and Disable you Compiler and clear/flush magento cache data. In most of the cases this would solve the issue.
Solution 2 : Improve PHP Memory Limit
If you can access php.ini OR use .htaccess in the root OR edit index.php add below line right after ini_set(‘display_errors’, 1);
Solution 3 : Design changes
If you have recently installed a new theme, try to switch the interface to a previously used one. Flush the Magento cache after each operation. Magento will switch to a default theme if it cannot find a custom one.