Title: Fatal error: Call to undefined function wp_using_ext_object_cache()
Last modified: August 21, 2016

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# Fatal error: Call to undefined function wp_using_ext_object_cache()

 *  [greenjeans1970](https://wordpress.org/support/users/greenjeans1970/)
 * (@greenjeans1970)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/)
 * Hello – I have done a manual upgrade of wordpress and am getting this error, 
   for both the query.php and option.php pages.
 * If I replace all the files/folders in the wp-includes directory, with clean versions
   from the install, then my site appears as normal. But after a few minutes or 
   sometimes several, the error comes up again.
 * Any ideas on what might be the issue(s)? Let me know if there’s anything I can
   do to correct the problem.
 * Thanks, Yuri

Viewing 9 replies - 1 through 9 (of 9 total)

 *  [Dave Naylor](https://wordpress.org/support/users/wpranger/)
 * (@wpranger)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359615)
 * Do you have caching enabled on your site? Empty/disable the cache and see if 
   that provides a cure.
 *  Thread Starter [greenjeans1970](https://wordpress.org/support/users/greenjeans1970/)
 * (@greenjeans1970)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359644)
 * Dumb question > where are the cache settings?
 *  [Dave Naylor](https://wordpress.org/support/users/wpranger/)
 * (@wpranger)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359680)
 * If you don’t know where they are, you’re probably not running a caching plugin,
   unless someone set the site up for you of course. Have a look at your active 
   plugins to see if there is one vaguely sounding like a cache.
 * Of course it might not be the cause of your issue. I’d be inclined to overwrite
   all the WordPress core files, not just the ones in wp-includes.
 *  Thread Starter [greenjeans1970](https://wordpress.org/support/users/greenjeans1970/)
 * (@greenjeans1970)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359756)
 * No, am not running any caching plugins, just aksimet. I’ve overwritten all the
   core files, and have now reinstalled wordpress a few times, with no success. 
   It’s always the same, after I reinstall the site appears fine, and then I get
   the error after a few minutes. Very frustrating. Could it be a server/hosting
   issue? I’m using Hostway, and have been for years.
 *  [riskamudrika](https://wordpress.org/support/users/riskamudrika/)
 * (@riskamudrika)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359757)
 * Try to enable wp_debug from wp-config.php, wordpress will provide information
   if any error from your themes
 *  Thread Starter [greenjeans1970](https://wordpress.org/support/users/greenjeans1970/)
 * (@greenjeans1970)
 * [12 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359758)
 * Still rendering that error.
 * Fatal error: Call to undefined function wp_using_ext_object_cache() in /home/
   vg001web04/67/55/2935567/web/wp-includes/option.php on line 445
 *  [jasonzshi](https://wordpress.org/support/users/jasonzshi/)
 * (@jasonzshi)
 * [12 years, 2 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359858)
 * Fatal error: Call to undefined function wp_using_ext_object_cache() in /srv/disk9/
   1486160/www/jasonzshi.co.nf/wp-includes/option.php on line 445
 *  [ChadMaestro](https://wordpress.org/support/users/chadmaestro/)
 * (@chadmaestro)
 * [12 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359870)
 * Hi all, this was the first result after googling the error. I also received a
   similar error when trying to install WooCommerce. I was attempting to install
   it on my local copy of WordPress. The solution, in my situation, was upgrading
   WP to the latest 3.8.1. I assume the latest plugin is incompatible with older
   versions of WP.
 *  [Patrick Rauland](https://wordpress.org/support/users/bftrick/)
 * (@bftrick)
 * [12 years ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359878)
 * I’ve seen this with other WooCommerce issues – an older version of WordPress.
   Just upgrade WordPress and that should solve that.

Viewing 9 replies - 1 through 9 (of 9 total)

The topic ‘Fatal error: Call to undefined function wp_using_ext_object_cache()’ 
is closed to new replies.

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 9 replies
 * 6 participants
 * Last reply from: [Patrick Rauland](https://wordpress.org/support/users/bftrick/)
 * Last activity: [12 years ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_using_ext_object_cache/#post-4359878)
 * Status: not resolved

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