Title: Cannot use output buffering error – stacktrace
Last modified: August 22, 2016

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# Cannot use output buffering error – stacktrace

 *  [gaspy](https://wordpress.org/support/users/gaspy/)
 * (@gaspy)
 * [11 years, 9 months ago](https://wordpress.org/support/topic/cannot-use-output-buffering-error-stacktrace/)
 * I get random errors with W3 Total Cache. This happens on 2 sites with different
   themes and plugins (common plugins are Captcha, WordPress SEO and iThemes Security)
 *     ```
       The error + stacktrace is:
       03-Sep-2014 07:26:32 UTC] PHP Fatal error:  Unknown: Cannot use output buffering in output buffering display handlers in Unknown on line 0
       [03-Sep-2014 07:26:32 UTC] PHP Stack trace:
       [03-Sep-2014 07:26:32 UTC] PHP   1. shutdown_action_hook() /var/www/mysite/cms/wp-includes/load.php:0
       [03-Sep-2014 07:26:32 UTC] PHP   2. do_action() /var/www/mysite/cms/wp-includes/load.php:573
       [03-Sep-2014 07:26:32 UTC] PHP   3. call_user_func_array() /var/www/mysite/cms/wp-includes/plugin.php:470
       [03-Sep-2014 07:26:32 UTC] PHP   4. wp_ob_end_flush_all() /var/www/mysite/cms/wp-includes/plugin.php:470
       [03-Sep-2014 07:26:32 UTC] PHP   5. ob_end_flush() /var/www/mysite/cms/wp-includes/functions.php:2935
       [03-Sep-2014 07:26:32 UTC] PHP   6. W3_Plugin_TotalCache->ob_callback() /var/www/mysite/cms/wp-includes/functions.php:2935
       [03-Sep-2014 07:26:32 UTC] PHP   7. w3tc_do_ob_callbacks() /var/www/mysite/cms/assets/plugins/w3-total-cache/lib/W3/Plugin/TotalCache.php:639
       [03-Sep-2014 07:26:32 UTC] PHP   8. call_user_func() /var/www/mysite/cms/assets/plugins/w3-total-cache/inc/functions/plugin.php:23
       [03-Sep-2014 07:26:32 UTC] PHP   9. W3_PgCache->ob_callback() /var/www/mysite/cms/assets/plugins/w3-total-cache/inc/functions/plugin.php:23
       [03-Sep-2014 07:26:32 UTC] PHP  10. W3_PgCache->_can_cache_buffer() /var/www/mysite/cms/assets/plugins/w3-total-cache/lib/W3/PgCache.php:337
       [03-Sep-2014 07:26:32 UTC] PHP  11. W3_PgCache->_send_headers() /var/www/mysite/cms/assets/plugins/w3-total-cache/lib/W3/PgCache.php:1547
       ```
   
 * Is it a known issue?
 * [https://wordpress.org/plugins/w3-total-cache/](https://wordpress.org/plugins/w3-total-cache/)

Viewing 1 replies (of 1 total)

 *  Thread Starter [gaspy](https://wordpress.org/support/users/gaspy/)
 * (@gaspy)
 * [11 years, 8 months ago](https://wordpress.org/support/topic/cannot-use-output-buffering-error-stacktrace/#post-5250603)
 * I selectively disabled Captcha, WordPress SEO and iThemes but the same error 
   persists.

Viewing 1 replies (of 1 total)

The topic ‘Cannot use output buffering error – stacktrace’ is closed to new replies.

 * ![](https://ps.w.org/w3-total-cache/assets/icon-256x256.png?rev=1041806)
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## Tags

 * [output buffering](https://wordpress.org/support/topic-tag/output-buffering/)

 * 1 reply
 * 1 participant
 * Last reply from: [gaspy](https://wordpress.org/support/users/gaspy/)
 * Last activity: [11 years, 8 months ago](https://wordpress.org/support/topic/cannot-use-output-buffering-error-stacktrace/#post-5250603)
 * Status: not resolved