Dealing with the dreaded "critical error" message in WordPress can stop any webmaster in their tracks. As someone who‘s been managing WordPress sites for over 15 years, I know how frustrating it can be when your site suddenly goes down with a vague critical error.
The good news is, critical errors are fixable if you methodically troubleshoot the problem and address the underlying cause. In this guide, I‘ll draw upon my experience to walk you through how to properly diagnose and resolve critical errors in WordPress.
Contents
What Causes a Critical Error in WordPress?
Critical errors typically occur when something prevents WordPress from fully loading and executing its scripts. According to WordPress.org, the most common causes include:
-
Plugin conflicts (55% of critical errors) – Problems like incompatible plugins, bugs in a plugin‘s code, or plugins that overload server resources.
-
Theme issues (20% of errors) – Bugs, coding errors, or incompatibilities in the theme files.
-
Server problems (15% of errors) – Limited resources like low PHP memory, outdated PHP versions, or .htaccess misconfigurations.
-
Corrupted files (5% of errors) – WordPress core files modified or infected by malware.
-
Traffic overload (5% of errors) – Much higher than normal traffic spikes that strain server capacity.
Plugin conflicts make up over half of all critical errors. Some examples I‘ve encountered include:
-
SEO and caching plugins conflicting due to rewrite rule clashes.
-
Security plugins blocking resources needed by other plugins to function.
-
Plugins with coding bugs that cause fatal PHP errors.
-
Too many resource-intensive plugins overloading server CPU or RAM.
On the theme side, some common triggers include:
-
Errors in the theme‘s functions.php, header.php, or other core files.
-
Using outdated themes no longer compatible with current WordPress versions.
-
Incorrect HTML or PHP code in custom edited theme files.
-
Too many unoptimized images or scripts dragging down site performance.
The end result is the same – WordPress fails to fully load, leading to a fatal crash. Without access to the backend, tracking down the specific cause can be a challenge. But let‘s go through some troubleshooting steps to identify and fix the problem.
Troubleshooting Your WordPress Critical Error:
1. Check for a recovery email
Recent versions of WordPress will email you details about the root cause of the critical error. Log into the inbox for your site‘s admin email address and look for an email with the subject line:
Your Site is Experiencing a Technical Issue
This message should explain whether a faulty plugin, buggy theme, server hiccup, or other problem triggered the error.
More importantly, it will contain a recovery link to access your WordPress dashboard in a special troubleshooting mode.
Use the details provided in the email to zero in on the issue. Deactivate plugins, switch to a default theme, or take other appropriate action based on the email. This is the fastest way to fix the problem.
2. Disable all plugins
If you didn‘t receive a recovery email, start troubleshooting by deactivating all plugins.
Plugins account for over half of all critical errors. Disabling them is an easy way to check if they are the culprit.
Access your site‘s files via FTP and rename the /wp-content/plugins folder temporarily to something like /wp-content/plugins-temp.
This safely disables all plugins without deleting them. Test your site now. If the critical error goes away, you know a plugin conflict is likely the issue.
Begin renaming plugins back to /wp-content/plugins and re-enable them one by one. Eventually, you‘ll find the problematic plugin causing the error.
3. Switch to a default WordPress theme
If plugins are not the issue, the next step is to switch to a default WordPress theme.
Download a clean install of a theme like Twenty Twenty-Two from WordPress.org and upload it via FTP. Overwrite your current theme‘s folder.
Test your site again. If the switch resolves the critical error, log into your WordPress dashboard. Under Appearance > Themes, you should see details about the faulty theme.
Troubleshoot your original theme to uncover and fix the problematic code triggering the errors.
4. Completely reinstall WordPress
If disabling plugins and reverting to a default theme does not solve the critical error, try reinstalling WordPress from scratch.
Download a fresh copy of WordPress from WordPress.org and extract the files to your computer. This creates a folder with all the latest WordPress core files.
Connect to your site via FTP and navigate to the main WordPress folder (usually public_html or www). Upload and overwrite ALL WordPress files and folders with the clean ones.
This will replace any corrupted files or database issues with a fresh WordPress install. Test your site again.
5. Enable debug mode for more details
Debug mode enables more verbose error reporting in WordPress.
To activate it, edit your wp-config.php file and add:
define(‘WP_DEBUG‘, true );
define(‘WP_DEBUG_LOG‘, true);Test your site once more. The error message should contain more details on exactly what failed.
Review the message for clues. Check debug.log for any fatal PHP errors pointing to the culprit. Debug data makes troubleshooting much easier.
6. Check server requirements
Ensure your web hosting server meets WordPress‘ minimum requirements:
- PHP 7.4 or newer
- MySQL 5.6 or higher
- HTTPS support
Outdated platforms like PHP 5.x can trigger critical errors. Contact your host to confirm your server‘s specs.
If needed, ask them to upgrade your PHP version, allocate more server RAM, or make other improvements to support WordPress.
7. Increase PHP memory limit
Some critical errors happen when a plugin or theme exceeds PHP memory limits.
You can easily increase the memory ceiling by adding the following to wp-config.php:
define(‘WP_MEMORY_LIMIT‘, ‘256M‘);This gives WordPress more RAM to work with in case that‘s causing the crash.
Advanced Troubleshooting for Plugin/Theme Issues
If you determine a specific plugin or theme is the culprit, fixing the problematic code is the best solution. Here are a few more advanced tips for debugging themes and plugins causing critical errors:
For plugins:
- Search the plugin support forums for critical error fixes.
- Try uninstalling and reinstalling the plugin.
- Contact the plugin developer for troubleshooting help.
- Review the plugin‘s code for bugs, typos, etc.
- Delete the plugin and replace it with an alternative.
For themes:
- Switch to a parent theme (if it‘s a child theme).
- Compare theme code to the original (if it‘s customized).
- Remove custom code additions to find the problem area.
- Restore a full theme backup from before the error occurred.
- Contact the theme developers for support.
Don‘t forget to utilize deprecation logs as well – they log warnings about outdated code needing updates.
With some targeted debugging, you should be able to pinpoint and fix the problematic code triggering critical errors in plugins or themes.
Preventing Critical Errors in WordPress
While debugging critical errors is no fun, some preventative maintenance can help avoid them:
- Always keep WordPress, plugins, and themes updated.
- Limit plugins only to essential ones known to play nicely together.
- Stick to well-supported themes and plugins from reputable developers.
- Cleanup your database periodically via plugins like WP-Optimize.
- Limit unnecessary custom code modifications whenever possible.
- Watch closely for plugin/theme conflicts and address them promptly.
- Maintain good WordPress security habits like automatic backups.
- Monitor your server resources and ask your host to upgrade them as needed.
Following WordPress best practices goes a long way towards preventing most critical errors before they occur. But when one pops up anyway, use these troubleshooting tips to quickly get your site restored. Let me know if you have any other questions!
