Fix the WordPress Critical Error (Step-by-Step Guide)

Learn how to fix the WordPress critical error that prevents your site from loading. Step-by-step guide with debugging, plugin/theme checks, and PHP fixes.

❌ What is the WordPress Critical Error?

This error usually shows as:

“There has been a critical error on your website.”

It means WordPress has hit a PHP or plugin/theme issue that prevents it from running.
Often caused by:

• A faulty plugin update
• Theme conflict
• PHP version incompatibility
• Memory limit reached

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✅ Step-by-Step Fix

Step 1: Enable Debug Mode

Edit your wp-config.php file and add:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

This saves errors in /wp-content/debug.log.

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Step 2: Deactivate Plugins

If you can’t access wp-admin:

cd /var/www/html/wp-content/
mv plugins plugins_backup
mkdir plugins

This deactivates all plugins. If site works → re-enable one by one to find the bad one.

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Step 3: Switch to Default Theme

Rename your active theme folder:

mv wp-content/themes/yourtheme wp-content/themes/yourtheme_backup

WordPress will load the default theme (like Twenty Twenty-Four).

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Step 4: Increase PHP Memory Limit

Edit wp-config.php:

define( 'WP_MEMORY_LIMIT', '256M' );

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Step 5: Check PHP Version

Run:

php -v

Make sure WordPress supports your version. (WordPress 6.x works best on PHP 8.1+).

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Step 6: Reinstall Core Files

Download fresh WordPress and upload everything except wp-content and wp-config.php.

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Step 7: Contact Hosting Provider

If none of the above fixes it, check your server error logs or ask your hosting support for the PHP/Apache/Nginx logs.

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⚡ Quick Recap

• The critical error is usually plugin or theme related.
• Fix by:
  1. Debugging logs
  2. Deactivating plugins
  3. Switching themes
  4. Increasing memory
  5. Checking PHP compatibility

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✅ Once fixed, turn off debug mode in wp-config.php:

define( 'WP_DEBUG', false );