title: Fatal error: session_start() after upgrading to Codeigniter 3
body: <p>I upgraded from <strong>Codeigniter 2 to 3</strong> and now I get this error with my <strong>CAS library</strong>:</p>
  
  <pre><code>A PHP Error was encountered
  
  Severity: Error
  
  Message: session_start() [function.session-start]: Failed to initialize storage module: user (path: C:\Windows\Temp)
  
  Filename: CAS/Client.php
  
  Line Number: 3588
  
  Backtrace:
  </code></pre>
  
  <p>It has something to do with session, which I guess CI3.0 handles it differently from CI2.0.</p>
  
  <p>I have the following in the <strong>config.php</strong></p>
  
  <pre><code>$config['sess_driver'] = 'files';
  $config['sess_cookie_name'] = 'ci_session';
  $config['sess_expiration'] = 7200;
  $config['sess_save_path'] = NULL;
  $config['sess_match_ip'] = FALSE;
  $config['sess_time_to_update'] = 300;
  $config['sess_regenerate_destroy'] = FALSE
  </code></pre>
  
  <p>;</p>
  
  <p>Any help will be highly appreciated. Thanks.</p>
  
  <p><strong>NEW:</strong></p>
  
  <p>I did a clean CI3.0.4 install and it seems like the problem is the CAS authentication library:
  <a href="https://github.com/eliasdorneles/code-igniter-cas-library" rel="nofollow">https://github.com/eliasdorneles/code-igniter-cas-library</a></p>
  
  <p>It worked with CI 2.x, but not with CI3.0. If I just not load the CAS module, everything works fine with regard to the session (I have no problem setting sessions, etc). But once I load the CAS there is a problem with the line <code>session_start()</code> at the <strong>CAS/Client.php</strong>. Any ideas?</p>