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How to Fix Pluggable.php File Errors in WordPress?

fix pluggable.php file errors

The “Pluggable.php File Error in WordPress” is a common issue when there’s a problem with the pluggable.php file, a core file responsible for loading functions that plugins or themes can overwrite. 

This error can lead to various problems, such as a blank page or a specific error message on your website. It often arises when you try to add a code snippet to your site or activate a new plugin. 

This guide will explore how to fix pluggable.php file errors in WordPress, ensuring your website runs smoothly again.

Error codePluggable.php File Errors
Error typeServer-Side Error
Error variationsPluggable.php File Errors
Error causes

  • Modified Functions

  • Syntax errors

  • Corrupted pluggable.php file

  • Incompatible plugins or themes

  • Conflicting Functions

What Causes Errors in Pluggable.php File?

Here we got some common causes of Pluggable.php File Errors in WordPress:

Modified Functions

When adding custom functions to the functions.php file in WordPress, you might encounter errors related to the pluggable.php File. This typically happens when your custom code conflicts with functions already defined in WordPress core or plugins.

Syntax Errors

Another reason is syntax errors in the code. This can occur when an error in a file relies on a function defined in the pluggable.php file.

Corrupted Pluggable.php File

The pluggable.php file can become corrupted or accidentally deleted, leading to errors.

Incompatible Plugins or Themes

Some plugins or themes may be incompatible with the version of WordPress or with other plugins or themes, causing issues with the pluggable.php file.

Conflicting Functions

One common reason is the presence of conflicting functions in PHP files. This can occur when a plugin or theme defines a function with the same name as a function defined in the pluggable.php file, causing a conflict that results in an error.

What does it Typically Show?

You might encounter a pluggable.php file error when adding code snippets or activating new plugins on your website. Sometimes, if a plugin or code snippet conflicts with WordPress’s core functions, you might see an error like this:

Warning: Cannot modify header information – headers already sent by (output started at /home/name/yourwebsite/wp-content/plugins/nameofplugin/plugin-file.php:99) in /home/name/yoursite/wp-includes/pluggable.php on line 1891’.
pluggable.php error

This error usually points to a problematic plugin. Try deactivating the plugin to see if that fixes the issue.

Pluggable.php file errors are often caused by poorly coded plugins or custom code snippets, not the file itself. Sometimes, the theme can also be the culprit.

Important: Sometimes, you can still work on your website even if the error appears in the admin area.

WordPress dashboard

Understanding the Pluggable.php Error

WordPress includes a file called pluggable.php in the wp-includes directory. This file contains core functions that you can override.

pluggable.php file

Some key pluggable functions include:

  • wp_mail: Used for sending emails. You can customize it for your email template.
  • wp_new_user_notification: Sends an email when a new user registers.
  • auth_redirect: Checks if a user is logged in and redirects them if not.
  • wp_password_change_notification: Sends an email when a password is changed.

These functions are essential, but you can modify them for customization.

However, if you try to override these functions with a plugin or code snippet and it’s not done correctly, you may encounter a pluggable.php file error. This error happens because the plugin or snippet fails to override the function properly.

Fixing Pluggable.php File Errors in WordPress

The Pluggable.php file is an essential part of WordPress, but modifying it directly is recommended only if you’re sure it’s the source of the error. Often, the issue lies elsewhere.

For instance, if you encounter an error like this:

“Warning: Cannot modify header information ‒ headers already sent by (output started at /home/username/thesite/wp-content/themes/mytheme/functions.php:282) in /home/username/thesite/wp-includes/pluggable.php on line 101″.

It indicates the real problem is in your theme’s functions.php file, specifically at line 282. Correcting or removing the problematic code, such as an extra space after a PHP closing tag ?>, often resolves the issue.

If you encounter errors in your functions.php file and are unsure how to fix them🥵.

Pro Tip😎: The functions.php file is part of your theme. Switching to a default WordPress theme can often resolve these errors. This approach helps you determine if the issue is related to your custom theme.

Switch to a Default WordPress Theme

  1. Go to the Appearance menu in your WordPress dashboard and click on Themes.
  1. Find a default WordPress theme, such as Twenty Twenty-Four, and click the “Activate” button.

Similarly, plugin conflicts can cause errors:

“Warning: Cannot modify header information ‒ headers already sent by (output started at /home/username/thesite/wp-content/plugins/name-of-plugin/plugin-example.php:244) in /home/username/thesite/wp-includes/pluggable.php on line 1189″.

In this case, deactivate the problematic plugin via your WordPress dashboard.

However, if the error affects your wordpress admin panel and you don’t access your WordPress dashboard, don’t hesitate. Then, here is a way to deactivate the conflict plugin using FTP or cPanel.

Steps – Deactivate a Conflict Plugin via FTP

  1. Connect to your server using an FTP client and navigate to the root folder of your website.
  2. Locate the wp-content folder and the plugins folder.
Deactivate a Conflict Plugin via FTP
  1. Find the conflicting plugin causing the Pluggable.php errors and rename its folder by adding “–deactivate” to the end.
deactivate plugins

Remember, Pluggable.php errors usually arise from issues in your theme or plugins, not the Pluggable.php file itself. Always check these first before making any direct edits to core files.


Pluggable.php file errors often come from badly coded themes, plugins, or mistakes in your WordPress files. Check and correct any custom code in your theme’s functions.php file to fix these errors.

The error message usually shows where the problem is, making it easier to find and fix. Remember, these errors usually start in your theme or plugins, not in the Pluggable.php file itself. Always check these areas first before editing any core files.

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