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Resolving Common WooCommerce Fatal Errors and 'Doing it Wrong' Warnings

26 threads Sep 7, 2025 Plugin → Woocommerce

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If your WooCommerce store has recently started throwing fatal errors or filling your error logs with warnings, you're not alone. A common theme across many recent support threads involves errors related to function calls made at the wrong time, missing methods, or type mismatches. This guide will help you understand why these errors occur and walk you through the most effective steps to resolve them.

Common Error Types and Their Causes

Based on community reports, the most frequent errors fall into a few key categories:

  • "Called Incorrectly" Warnings: Errors like wc_get_order was called incorrectly or get_cart was called incorrectly indicate that a function is being called before WordPress or WooCommerce has fully loaded the necessary components (e.g., before post types are registered or the wp_loaded action has fired). This is often caused by code in a theme or another plugin that executes too early.
  • Fatal Errors: Uncaught TypeError: These occur when a function receives a variable of the wrong type, such as null being passed where a string is expected. A prevalent example is the strpos(): Argument #1 ($haystack) must be of type string, null given error in src/Blocks/BlockPatterns.php on or around line 251. This was a known issue related to remote block patterns that has been addressed in recent updates.
  • Fatal Errors: Call to undefined method: Errors like Call to undefined method WC_Order::get_report_customer_id() suggest a code incompatibility, often because a custom or third-party plugin is using a method that has been deprecated, renamed, or removed in a newer version of WooCommerce.
  • Fatal Errors: Class not found: Errors such as Class "WooCommerceLogger" not found typically point to an outdated or malfunctioning extension that is trying to load a dependency which is no longer present or has been changed.

Step-by-Step Troubleshooting Guide

Follow these steps to identify and fix the root cause of the error on your site.

1. Implement a Conflict Test

The vast majority of these errors are caused by conflicts between plugins or with your theme.

  1. Switch to a Default Theme: Temporarily activate a default WordPress theme like Twenty Twenty-Four or Storefront. If the error disappears, the issue lies with your original theme.
  2. Disable All Plugins: Deactivate all plugins except WooCommerce. If this resolves the issue, you have a plugin conflict.
  3. Re-enable Plugins One by One: Reactivate your other plugins one at a time, checking for the error after each activation. This will help you identify the specific plugin causing the problem.

2. Update Everything

Many of these issues, particularly the BlockPatterns.php error, have been patched in subsequent WooCommerce releases. Ensure all your software is up to date:

  • Update WooCommerce to the latest version.
  • Update your theme and all other plugins, especially any WooCommerce extensions like payment gateways or booking systems.
  • If you identified a problematic plugin in Step 1, check the developer's website for an update or contact their support.

3. Clear Transients and Caches

For the specific BlockPatterns.php error, clearing a transient can often provide immediate relief. You can do this in two ways:

  • Using WP-CLI: Run the command: wp transient delete ptk_patterns
  • Manually via Database: Run the following SQL query in your database management tool (like phpMyAdmin), ensuring you use your correct database prefix: 
    DELETE FROM wp_options WHERE option_name = '_transient_ptk_patterns';

Also, clear any server-side (Object Caching, Varnish) and plugin-based (e.g., WP Rocket, W3 Total Cache) caches.

4. Check for Corrupted Installations

If you are encountering syntax errors (e.g., unexpected ')'), your WooCommerce plugin files may have become corrupted during an update.

  1. In your WordPress dashboard, navigate to Plugins > Installed Plugins.
  2. Deactivate and then delete the WooCommerce plugin. Important: Do not worry; your order and product data is stored in your database and will not be lost.
  3. Go to Plugins > Add New and reinstall WooCommerce directly from the WordPress plugin repository.

When to Seek Further Help

If the steps above do not resolve your issue, the error is likely highly specific. Your next best step is to search for the exact error message online. Repositories like the WooCommerce GitHub Issues page are excellent resources where many known bugs are tracked and discussed by the community and the WooCommerce team.

By systematically working through these steps, you can usually isolate and resolve the problem, getting your store back to running smoothly.

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