Title: Fatal Error Call to undefined function wp_update_custom_css_post()
Last modified: January 18, 2018

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# Fatal Error Call to undefined function wp_update_custom_css_post()

 *  [woodenwindowsills](https://wordpress.org/support/users/woodenwindowsills/)
 * (@woodenwindowsills)
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/)
 * HELP!
 * I’ve just updated my theme on WordPress (didn’t change it, just clicked “update
   now” as it told me it had an available update) and I’ve managed to mess up both
   my blog page, AND I now can’t even access where I edit my WordPress at all. The
   url [http://www.woodenwindowsills.co.uk](http://www.woodenwindowsills.co.uk) 
   now just goes to this error page saying:
 * Fatal error: Call to undefined function wp_update_custom_css_post() in /websites/
   123reg/LinuxPackage23/sp/_a/ce/sp-ace.co/public_html/WoodenWindowSills/wp-content/
   themes/activello/functions.php on line 125
 * Do you have any idea why this has happened or any wisdom for how to sort it?
 * I know nothing about the technicalities of websites (I usually just log into 
   my wordpress page and then I’m set), so please explain all solutions in the most
   basic terms, I’m panicking that I won’t be able to get it back!
 * Thanks,
 * Alice
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffatal-error-call-to-undefined-function-wp_update_custom_css_post%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 6 replies - 1 through 6 (of 6 total)

 *  [Muhammad Javed](https://wordpress.org/support/users/leadsoft/)
 * (@leadsoft)
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9877806)
 * Hello,
    this function is not exists into your site wp_update_custom_css_post.
   for quick solution you need to go in your function.php and add this small code.
   function wp_update_custom_css_post(){ return ; } actually above error call this
   function which is not exists into your site after adding this your site will 
   work then check what is missing, this function name showes there would be some
   css issue. Thanks
    -  This reply was modified 8 years, 3 months ago by [Muhammad Javed](https://wordpress.org/support/users/leadsoft/).
 *  [Andrew Nevins](https://wordpress.org/support/users/anevins/)
 * (@anevins)
 * WCLDN 2018 Contributor | Volunteer support
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9877841)
 * Can you try reinstalling just the theme? You will need FTP access/ access to 
   a file manager through your _hosting provider’s _control panel.
 * Once you have access,
    - Download the theme to your computer: [https://wordpress.org/themes/activello/](https://wordpress.org/themes/activello/)
    - Unzip it
    - Using FTP or your File Manager tool, go to the ‘wp-content/themes’ folder
    - Upload the ‘activello’ (unzipped on your computer) folder there and choose
      to overwrite/ replace any duplicate file
 *  -  This reply was modified 8 years, 3 months ago by [Andrew Nevins](https://wordpress.org/support/users/anevins/).
 *  [Andrew Nevins](https://wordpress.org/support/users/anevins/)
 * (@anevins)
 * WCLDN 2018 Contributor | Volunteer support
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9877872)
 * I don’t know if you’ve changes to the theme’s files so it’s best to make a backup
   first.
 *  Thread Starter [woodenwindowsills](https://wordpress.org/support/users/woodenwindowsills/)
 * (@woodenwindowsills)
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9877983)
 * Thanks for all of your suggestions, how do I do a backup? I can’t access anything
   but that error page, whether I try and sign in as I usually would or just on 
   the site itself?
 *  [Andrew Nevins](https://wordpress.org/support/users/anevins/)
 * (@anevins)
 * WCLDN 2018 Contributor | Volunteer support
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9878067)
 * Copy the existing theme folder using FTP/ your hosting provider’s file manager
   tool and put it somewhere safe.
 *  [Rajan Vijayan](https://wordpress.org/support/users/rajanit2000/)
 * (@rajanit2000)
 * [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9878425)
 * Hi [@woodenwindowsills](https://wordpress.org/support/users/woodenwindowsills/).,
 * You can get backup with FTP or CPanel File manager.
 * Try to reinstall the theme manually
 * Download this theme [https://downloads.wordpress.org/theme/activello.1.3.6.zip](https://downloads.wordpress.org/theme/activello.1.3.6.zip)
 * And extract your wp-content/themes folder manually (using FTP)
 * Thanks
    Rajan V

Viewing 6 replies - 1 through 6 (of 6 total)

The topic ‘Fatal Error Call to undefined function wp_update_custom_css_post()’ is
closed to new replies.

## Tags

 * [colorlib](https://wordpress.org/support/topic-tag/colorlib/)
 * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 6 replies
 * 4 participants
 * Last reply from: [Rajan Vijayan](https://wordpress.org/support/users/rajanit2000/)
 * Last activity: [8 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_update_custom_css_post/#post-9878425)
 * Status: not resolved

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