Answers.Body: <p>I am not sure WHAT was different, but I just went back and reloaded the System.php file again, and it is working now.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-06-08T08:15:15.003Z
Answers.Text: I currently have a similar issue and I am also running on Wordpress: (Warning: Cannot modify header information - headers already sent by (output started at .../wp-content/plugins/civicrm/civicrm/CRM/Core/Task.php:132) in .../wp-content/plugins/civicrm/civicrm/CRM/Utils/System/Base.php on line 926). This occurs when searching for event participants in the Events menu. When you say you reloaded the System.php again, what do you mean by "reloaded"?
Answers.UserDisplayName: Sudesh
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-05-13T04:37:48.150Z
Answers.LastActivityDate: 2017-05-13T04:37:48.150Z
Answers.UserDisplayName: Tiffany Carra
Body: <p>I am getting the following errors when doing various tasks in and around CiviCRM only</p>
  
  <pre><code>Warning: Cannot modify header information - headers already sent by (output started at .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php:1) in .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System/Base.php on line 912
  </code></pre>
  
  <p>When hitting save on things like clearing cache and updating paths. If I just hit refresh the page loads right up, but won't on the original button press.  </p>
  
  <p>and </p>
  
  <pre><code>Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php:1) in .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Core/Session.php on line 127
  </code></pre>
  
  <p>When running cron jobs. I know these are probably related, but would really love to get them fixed as the last one is blocking cron from running via url. </p>
  
  <p>Wordpress Version: 4.7.4
  CiviCRM Version: 4.7.19</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-10T21:01:41.287Z
Comments.Text: Any other plugins installed? Does it go away if you deactivate CiviCRM?
Comments.UserDisplayName: Christian Wach
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-10T23:02:45.413Z
Comments.Text: It only comes up IN CiviCRM when I execute stuff. Like hitting Print on a Report button or running the Cron Job or the two outlined above. The pages only display those errors. 
  
  I do have other plugins activated. I suppose I can try that.
Comments.UserDisplayName: Tiffany Carra
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-10T23:41:35.200Z
Comments.Text: Deactivated all Wordpress Plugins, same thing. I'll check the 3 remaining extensions that I did not deactivate earlier
Comments.UserDisplayName: Tiffany Carra
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-11T15:12:59.657Z
Comments.Text: Disabled all extensions also and no change.
Comments.UserDisplayName: Tiffany Carra
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-12T15:54:42.250Z
Comments.Text: The warnings suggest that you look at the `wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php` file to see if it's got whitespace at the top of it for some reason. Have you looked there?
Comments.UserDisplayName: Christian Wach
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-05-12T19:58:31.557Z
Comments.Text: I did look at the file and saw no whitespaces. I even reuploaded the file from the most recent download.
Comments.UserDisplayName: Tiffany Carra
Tags: <wordpress><error><cron-job><cron>
Title: Header Issues On Wordpress Installation
ThreadText: # Header Issues On Wordpress Installation
  
  (Asked by: username_0 on 2017-05-10)
  
  I am getting the following errors when doing various tasks in and around CiviCRM only
  
  ```
  Warning: Cannot modify header information - headers already sent by (output started at .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php:1) in .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System/Base.php on line 912
  
  ```
  
  When hitting save on things like clearing cache and updating paths. If I just hit refresh the page loads right up, but won't on the original button press.
  
  and
  
  ```
  Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php:1) in .../public_html/wp-content/plugins/civicrm/civicrm/CRM/Core/Session.php on line 127
  
  ```
  
  When running cron jobs. I know these are probably related, but would really love to get them fixed as the last one is blocking cron from running via url.
  
  Wordpress Version: 4.7.4
  CiviCRM Version: 4.7.19
  
  **Tags:** wordpress, error, cron-job, cron
  
  > **Comments:**
  > **username_1**: Any other plugins installed? Does it go away if you deactivate CiviCRM?  
  > **username_0**: It only comes up IN CiviCRM when I execute stuff. Like hitting Print on a Report button or running the Cron Job or the two outlined above. The pages only display those errors.   I do have other plugins activated. I suppose I can try that.  
  > **username_0**: Deactivated all Wordpress Plugins, same thing. I'll check the 3 remaining extensions that I did not deactivate earlier  
  > **username_0**: Disabled all extensions also and no change.  
  > **username_1**: The warnings suggest that you look at the `wp-content/plugins/civicrm/civicrm/CRM/Utils/System.php` file to see if it's got whitespace at the top of it for some reason. Have you looked there?  
  > **username_0**: I did look at the file and saw no whitespaces. I even reuploaded the file from the most recent download.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2017-05-13. Score: 0 | Accepted answer
  
  I am not sure WHAT was different, but I just went back and reloaded the System.php file again, and it is working now.
  
  > **Comments:**
  > **username_2**: I currently have a similar issue and I am also running on Wordpress: (Warning: Cannot modify header information - headers already sent by (output started at .../wp-content/plugins/civicrm/civicrm/CRM/Core/Task.php:132) in .../wp-content/plugins/civicrm/civicrm/CRM/Utils/System/Base.php on line 926). This occurs when searching for event participants in the Events menu. When you say you reloaded the System.php again, what do you mean by "reloaded"?  
  
  ---
  
  