title: Wordpress: Cannot login in after upgrade - redirects to blank page
body: <p>I updated a clients Wordpress to 3.5.2 and now cannot login via wp-admin.</p>
  
  <p>The login form appears but once I hit the Log In button I am just redirect to a blank page with a single <code>.</code> on it. Same happens if I enter the wrong password.</p>
  
  <p>I have checked out the <a href="http://codex.wordpress.org/Login_Trouble" rel="nofollow">Login Trouble Codex</a> and tried replacing the wp-login.php file and disabling all plugins to no affect. I get the same issue occuring.</p>
  
  <p>Front of the site seems fine.</p>
  
  <p>What appreas in debug:</p>
  
  <pre><code>Warning: Cannot modify header information - headers already sent by (output started at /home/stretton/public_html/fo/wp-content/themes/freya/lib/widgets/banners-125.php:13) in /home/stretton/public_html/fo/wp-login.php on line 369
  
  Warning: Cannot modify header information - headers already sent by (output started at /home/stretton/public_html/fo/wp-content/themes/freya/lib/widgets/banners-125.php:13) in /home/stretton/public_html/fo/wp-login.php on line 381
  </code></pre>
  
  <p>EDIT: I have also tried:</p>
  
  <ul>
  <li>Renaming my theme to defualt it to the twentytwelve theme</li>
  <li>Renaming the plugins directory</li>
  <li>Removing the widgets directory</li>
  <li>Replacing WP-Admin with from a fresh download</li>
  </ul>
  
  <p>No luck with these either</p>