Title: Error in WordPress
Last modified: October 5, 2026

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# Error in WordPress

 *  [rmj6969](https://wordpress.org/support/users/rmj6969/)
 * (@rmj6969)
 * [3 days, 8 hours ago](https://wordpress.org/support/topic/error-in-wordpress-7/)
 * Site was working, now getting an error page, below are the errors
 * PHP Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback)
   must be a valid callback, function “_wp_register_default_icon_collections” not
   found or invalid function name in C:\inetpub\vhosts\rnwritenow.com\httpdocs\wp-
   includes\class-wp-hook.php:353 Stack trace: #0 C:\inetpub\vhosts\rnwritenow.com\
   httpdocs\wp-includes\class-wp-hook.php(377): WP_Hook->apply_filters() #1 C:\inetpub\
   vhosts\rnwritenow.com\httpdocs\wp-includes\plugin.php(522): WP_Hook->do_action()#
   2 C:\inetpub\vhosts\rnwritenow.com\httpdocs\wp-settings.php(771): do_action()#
   3 C:\Program Files (x86)\Plesk\Additional\modules\wp-toolkit\wp-cli\vendor\wp-
   cli\wp-cli\php\WP_CLI\Runner.php(1394): require(‘…’) #4 C:\Program Files (x86)\
   Plesk\Additional\modules\wp-toolkit\wp-cli\vendor\wp-cli\wp-cli\php\WP_CLI\Runner.
   php(1313): WP_CLI\Runner->load_wordpress() #5 C:\Program Files (x86)\Plesk\Additional\
   modules\wp-toolkit\wp-cli\vendor\wp-cli\wp-cli\php\WP_CLI\Bootstrap\LaunchRunner.
   php(28): WP_CLI\Runner->start() #6 C:\Program Files (x86)\Plesk\Additional\modules\
   wp-toolkit\wp-cli\vendor\wp-cli\wp-cli\php\bootstrap.php(84): WP_CLI\Bootstrap\
   LaunchRunner->process() #7 C:\Program Files (x86)\Plesk\Additional\modules\wp-
   toolkit\wp-cli\vendor\wp-cli\wp-cli\php\wp-cli.php(35): WP_CLI\bootstrap() #8
   C:\Program Files (x86)\Plesk\Additional\modules\wp-toolkit\wp-cli\vendor\wp-cli\
   wp-cli\php\boot-fs.php(17): require_once(‘…’) #9 C:\Program Files (x86)\Plesk\
   Additional\modules\wp-toolkit\wp-cli\wpt-wp-cli.php(49): require_once(‘…’) #10{
   main} thrown in C:\inetpub\vhosts\rnwritenow.com\httpdocs\wp-includes\class-wp-
   hook.php on line 353 Fatal error: Uncaught TypeError: call_user_func_array():
   Argument #1 ($callback) must be a valid callback, function “_wp_register_default_icon_collections”
   not found or invalid function name in C:\inetpub\vhosts\rnwritenow.com\httpdocs\
   wp-includes\class-wp-hook.php:353 Stack trace: #0 C:\inetpub\vhosts\rnwritenow.
   com\httpdocs\wp-includes\class-wp-hook.php(377
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ferror-in-wordpress-7%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Moderator [threadi](https://wordpress.org/support/users/threadi/)
 * (@threadi)
 * [3 days, 8 hours ago](https://wordpress.org/support/topic/error-in-wordpress-7/#post-19037056)
 * It looks like the WordPress core wasn’t uploaded completely. I’d recommend performing
   a manual update as described here: [https://wordpress.org/documentation/article/updating-wordpress/#manual-update](https://wordpress.org/documentation/article/updating-wordpress/#manual-update)
 *  [Carl Peeter](https://wordpress.org/support/users/carlpeeter32/)
 * (@carlpeeter32)
 * [2 days, 22 hours ago](https://wordpress.org/support/topic/error-in-wordpress-7/#post-19037327)
 * In addition to threadi’s suggestion: that specific error is also a classic sign
   of a plugin registering a hook callback that no longer exists, so if the manual
   update doesn’t fix it, try deactivating all plugins via FTP (rename the wp-content/
   plugins folder) and see if the site comes back. If it does, rename the folder
   back and reactivate the plugins one by one to find the culprit.

Viewing 2 replies - 1 through 2 (of 2 total)

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to reply to this topic.

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 2 replies
 * 3 participants
 * Last reply from: [Carl Peeter](https://wordpress.org/support/users/carlpeeter32/)
 * Last activity: [2 days, 22 hours ago](https://wordpress.org/support/topic/error-in-wordpress-7/#post-19037327)
 * Status: not resolved

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