Troubleshoot core file errors in WordPress

You can use the steps below to help diagnose whether an error is related to WordPress core files.

Prepare your WordPress site for the troubleshooting:

1. You should always make a backup of your site before performing any troubleshooting.
2. Disable any caching plugins. If you do not have access to your WordPress dashboard, you can disable the plugins in the database or with FTP.
3. Disable WP_CACHE if your site uses it.

Look for a core file-related error:

1. Enable WordPress debug mode.
2. Visit your site and check to see if there is a PHP error.
3. If there is a PHP error, check to see if a WordPress core file or folder is referenced in the file path.

   Note: Often these errors will reference a file in the wp-admin or wp-includes folders.

   Below is an example:
   

   Fatal error: require(): Failed opening required '/home/user/public_html/wp-includes/class-wp.php'

4. If the file path in the error contains a reference to a core file or folder, then you can move on to fixing the issue.
5. If the error isn't visible on your website, then you'll need to expose the error:
   • View Linux error logs in cPanel.
   • Enable Windows detailed errors in Plesk.
6. If the logs or detailed errors show a PHP error related to a core file, then you can begin fixing it.
7. Disable WordPress debug mode in the wp-config.php file by changing WP_DEBUG from true to false.

Related steps

• After confirming the problem is related to your WordPress core files, you can move on to fix WordPress core file errors.

More info

• Troubleshooting WordPress
• Disable WordPress plugins in the database
• Disable a WordPress plugin with FTP