Fatal error..can't sign into my WP site to try and deactivate naughty plugins. Help!

Question

dear sages received this when trying to either access my site URL, or sign into WP admin:

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "_wp_footnotes_kses_init" not found or invalid function name in /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/class-wp-hook.php:308 Stack trace: #0 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array) #1 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #2 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/pluggable.php(48): do_action('set_current_use...') #3 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/user.php(3606): wp_set_current_user(0) #4 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/pluggable.php(70): _wp_get_current_user() #5 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/class-wp.php(650): wp_get_current_user() #6 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-settings.php(604): WP->init() #7 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-config.php(109): require_once('/home/clients/c...') #8 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-load.php(50): require_once('/home/clients/c...') #9 /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-blog-header.php(13): require_once('/home/clients/c...') #10 /home/clients/c65c360040d19a9c974b291482fa7a09/web/index.php(17): require('/home/clients/c...') #11 {main} thrown in /home/clients/c65c360040d19a9c974b291482fa7a09/web/wp-includes/class-wp-hook.php on line 308

Just noticed today, but I did recall getting an email about an auto update that occurred 3 days ago...probably related from what I've read this far.

How can I get back into my dashboard to have a look? What could culprit be?

Many thanks in advance for any beacons of hope.

Answer 1

Log in via (S)FTP. Rename each plugin directory one by one (adding a letter to the end works) and try to load the site. When you've identified the problem one, rename the others back. You'll need to re-enable them in the Dashboard.

Answer 2

This is already raised with WordPress core team, you can find the details in this ticket.

https://core.trac.wordpress.org/ticket/61489#comment:37

Answer 3

I would like to add that you can restore your site to the last working version by restoring the backup in your hosting provider's back end.

Usually when I have a fatal error, it happens right after I activate a faulty plugin, so I know what plugin caused the fatal error. If the fatal error causes me to lose access to the wordpress dashboard, I log in to my hosting provider's dashboard and find the plugin that caused the issue and delete it, and the site will be fine again. This way I don't have to restore an older version of the site which takes time to do and could mean I lose new content.