Resolve a Critical Error on WordPress

For the video, I borrowed one from Digital-Cookie, which is excellent and does the job ;)

Imagine your WordPress website as a racing car going at full speed. Everything is running perfectly, visitors are pouring in, the engine is purring with pleasure… And then, suddenly, it crashes. A “critical error” message appears, blocking access to your WordPress dashboard and to the rest of your site. Panic on board?

Understanding the Critical Error on WordPress

Actually, no panic! Before launching into complex repairs, it is essential to understand what a critical error really is, why it occurs and what its consequences are for the functioning of your website. This is the indispensable starting point for getting your site back on track and preventing this kind of mishap from happening again.

Let this be clear: we’ve all been there — it’s all part of the learning curve!

What is a Critical Error on WordPress?

A critical error on WordPress is a bit like a code red in a hospital. WordPress encounters a problem so serious that it can no longer function normally. Concretely, this often results in a white screen, a terse error message (“There has been a critical error on this website”), and the impossibility of accessing the admin area.

This error can come from various places: a faulty plugin, an incompatible WordPress theme, or even a problem at the CMS core level. It’s as if one of the vital organs of your car has broken down.

Why Has a Critical Error Appeared on This Site? Common Causes

Identifying the origin of the problem is already half the battle. Several factors can cause a WordPress critical error. Among the most common WordPress errors, you will find:

• Plugin incompatibility: A poorly coded or incompatible plugin can cause conflicts and crash the site. It’s like installing a non-compliant part in a machine.

• Faulty themes: In the same way, a poorly designed or outdated WordPress theme can be the cause of this error. You need to make sure the default theme is up to date.

• PHP errors: PHP errors are often related to code problems in plugins or themes. WordPress uses PHP to function, so errors at this level can paralyse the site.

• PHP memory limit exceeded: WordPress, like any application, needs resources to function. If the memory limit allocated to PHP is too low, it can cause errors, especially on a site with many plugins or high traffic.

The Consequences of a Critical Error on Your Website’s Functioning

A critical error on your website is more than just an error message. It’s a real roadblock to the proper functioning of your site.

• Site unavailability: The most immediate consequence is that your website becomes inaccessible to your visitors. Imagine the frustration of someone trying to access your site and landing on a white screen…

• Loss of traffic and revenue: If your site is down, you lose visitors, prospects, and potentially revenue.

• Impact on SEO: Search engines like Google don’t like sites that don’t work. Prolonged unavailability can negatively impact your ranking.

• Brand image damage: A site that crashes regularly gives an unprofessional image.

In short, a critical error on your site is a bit like a storm that ravages your garden. You need to act quickly to repair the damage and put things in order. The good news? With the right methods, it is possible to restore everything very quickly.

Diagnosing the Critical Error on Your WordPress Site

Now that you understand the extent of the problem, let’s move on to the investigation phase. How do you unmask the culprit that caused this critical error? You’ll need to play web detective to track down the origin of the problem.

Enabling Debug Mode to Identify PHP Errors

WordPress’s debug mode is a bit like a stethoscope. It allows you to listen to WordPress’s heartbeat and spot anomalies. By enabling it, you will force WordPress to display the PHP errors hiding behind the white screen of death. These errors can give you valuable clues about the cause of this error. To enable debug mode, you need to dive into the site’s files.

Connect to your web server via FTP (if you don’t know how to do this, check out this excellent training by Digital Cookie), open the wp-config.php file and look for the line define( 'WP_DEBUG', false );.

You will then modify this line to define( 'WP_DEBUG', true );. Save the file and reload your web page. You should now see error messages.

Analysing Server Logs for a Thorough Investigation

If debug mode is not enough, it is time to move on to the next level: analysing server logs. Logs are files that record the activity of your web server. They contain valuable information about the errors that have occurred, the requests that have failed, and much more. It’s like going through a ship’s logbook to understand what went wrong. Analysing these logs can reveal the cause of this error.

Again, you need to go through FTP, or directly through your hosting provider. They generally have a server management tool that allows you to analyse the logs.

Checking Recent Extensions and Themes: A Frequent Source of Errors

Extensions and themes are very, very often the cause of this critical error. Think of them as added parts you install in your car. If a part is faulty or incompatible, it can crash the whole system.

It is therefore essential to check whether a recently installed or updated extension or theme could be the source of the problem. The good news is that there are simple ways to deactivate extensions and revert to a default theme to test whether the problem comes from there.

Step-by-Step Solutions to Fix a Critical Error on WordPress

Now, let’s get down to business: how do you fix this critical error and get your website back on track? We’re going to explore several approaches together, from the most basic to the most advanced, so that you can get your WordPress site back in full working order.

Make a Complete Backup of Your Site Before Any Intervention

The first thing to do is to make sure you have a fallback solution in case of complications.

Yes, it can happen to anyone. Touch wood: it has never happened to me to “lose” a site. But I know people it has happened to, so it’s better to be careful.

Before launching into fixing this error, make a complete backup of your WordPress site. It’s like taking out insurance: you hope you’ll never need it, but if things go wrong, you’ll be glad you have it. A backup will allow you to restore the site to a previous state if the manipulations make the situation worse.

You’ll have to do it manually, as the back office is unavailable (thanks to Carole - my WP coach - for pointing out the oversight).

Deactivate Extensions to Isolate the Origin of the Problem

Extensions are a bit like apps on a smartphone. They add features to the site, but they can also be a source of problems if they are poorly coded or incompatible.

To identify whether an extension is at the origin of this critical error, the simplest method is to deactivate them one by one. It’s like unplugging electrical appliances one by one to identify which one is blowing the fuses.

To do this, you need to connect via FTP, and rename the extensions to “extensionnameOLD” (or add something to the end to modify the address of their file).

Then try restarting the site: if it comes back, you’ve found the extension that was causing the error.

Restore Your Website from a Recent Backup

If you are lucky enough to have a recent backup, it’s a bit like having a time machine. Restoring your site from a backup will allow you to return to a state where everything was working correctly. It’s a radical solution, but often effective for getting rid of a critical error.

Personally, this would be my last resort: I much prefer knowing where the error came from to avoid resolving it again. And that’s how you learn, after all.

Replace the Active Theme with a Default WordPress Theme

Sometimes the problem doesn’t come from extensions, but from the theme. The theme is a bit like the bodywork of a car: it gives the visual appearance of the site. If the theme is poorly coded or incompatible with an extension, it can cause a critical error. To test whether the theme is the source of the problem, you can temporarily replace it with a default WordPress theme, like Twenty Twenty-Five.

Increase the PHP Memory Limit Allocated to WordPress

WordPress, like any web application, needs memory to function correctly. If the PHP memory limit allocated to WordPress is too low, it can cause a critical error, especially if you use many extensions. Increasing this limit can sometimes be enough to resolve the problem.

To do this, open the wp-config.php file and look for the line

define( 'WP_MEMORY_LIMIT', '64M' );

Change the value of this line to

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

Save the file and reload your web page.

Sometimes you’ll also need to check the memory limit on the server side, so don’t hesitate to involve your hosting provider if you think that’s where the issue lies (spoiler: I’d be surprised).

Resolve Syntax Errors in Your Site’s Files

A syntax error in a PHP file is a bit like a typo in a mathematical formula. It can prevent the code from executing correctly and cause a critical error. If you have recently modified files, check the syntax carefully to make sure there are no errors.

Logically, if this is what happened to you, you’re not reading these lines, because you’re supposed to know what you’re doing…

Reinstall the WordPress Core to Fix Corrupted Files

In rare cases, the WordPress core files can be corrupted, which can cause a critical error. Reinstalling the WordPress core is like reinstalling an operating system on a computer. This can resolve the problem if the core files are damaged.

Preventive Measures to Avoid Critical Errors in the Future

Now that you know how to fix a critical error on WordPress, let’s put all the odds in your favour to avoid having one again.

Prevention is better than cure, isn’t it? Imagine your website is a house: regular maintenance and a few simple precautions can save you a lot of trouble. Let’s look together at some essential preventive measures to keep your site in top shape and avoid unpleasant surprises.

Keep WordPress, Themes and Extensions Up to Date

An up-to-date WordPress site is a secure site. WordPress, theme and extension updates often contain important security fixes and performance improvements.

Neglecting these updates is like leaving the windows of a house open to burglars. They also fix potential errors and ensure compatibility between the various elements of your site.

Enable automatic updates to simplify maintenance and protect yourself against security vulnerabilities. It’s a simple gesture that can save you a lot of trouble! An updated site is a site that works better and is less vulnerable to errors.

But be careful, you should always make sure you have a working backup to hand! For this reason, I personally don’t use automatic updates, and I prefer to perform updates manually on a very regular basis.

The backup plugin I use makes an automatic backup of extensions with each update, with the option to roll back in case of a problem. I have also set up an automatic backup strategy for my WordPress site, with a regular backup to an external hard drive.

And since I’m paranoid (lightning struck my apartment 15 years ago), I also have redundancy for all my sites on two other servers.

Just in case…

Choose Extensions and Themes from Reliable Sources

The choice of extensions and themes is crucial for the health of your site. Using extensions and themes from unreliable sources is like inviting strangers into your home.

Make sure you download your extensions and themes from the official WordPress directory or from recognised developers. Check ratings, comments and the date of the last update before installing anything.

A poorly coded extension or a dodgy theme can cause a critical error or compromise the security of your site. Prioritise quality over quantity, and trust reliable sources. It’s a long-term investment for the stability of your website.

Monitor Your Site’s Performance and Optimise the Database

The health of your WordPress site also depends on its performance. A slow, poorly optimised site is more likely to encounter problems, including critical errors. Regularly monitor your site’s loading speed and optimise the database to remove unnecessary data.

Use a caching plugin to improve performance and reduce the load on the server. A clean database and a fast site means an optimal user experience and a site less prone to errors. It’s like changing the oil in a car: it allows it to function at its best.

Implement a Regular and Automatic Backup Strategy

It cannot be said often enough: regular backups are the key to peace of mind. Imagine your site is a sandcastle: a wave can sweep everything away in an instant. Set up an automatic backup strategy to back up the site, files and database at regular intervals.

Store these backups in a safe place, such as a cloud storage service or an external hard drive.

If something goes wrong, you can restore your site in a few clicks and avoid panic. It’s like having a plan B in all circumstances. Don’t neglect this essential aspect of site maintenance!

Use a plugin like WPVivid Backup for this — it works very well.

Strengthen the Security of Your WordPress Website

The security of your WordPress site is essential to avoid critical errors. A poorly secured site is an easy target for hackers, who can inject malicious code and cause fatal errors.

Use a strong password, change it regularly, and enable two-factor authentication to strengthen the security of your WordPress dashboard.

Install a security plugin to protect your site against common attacks, such as SQL injections and brute force attacks.

Implementing a rigorous security policy is like installing an alarm system in your home: it deters intruders and protects you from unpleasant surprises. A secure website is a site that works better and is less exposed to risks.

Useful Resources and Support for Resolving WordPress Errors

You’ve tried everything and the critical error persists on your WordPress site? Don’t panic, there are resources and communities ready to help you!

The Official WordPress Documentation: An Invaluable Guide

The official WordPress documentation is a bit like the bible for WordPress users. It’s a mine of valuable information on all aspects of WordPress, including error resolution. You will find detailed guides, tutorials, code examples and FAQs to help you understand how WordPress works and resolve common problems.

It’s an excellent starting point for diagnosing and fixing a critical error.

WordPress Support Forums: Getting Help from the Community

WordPress support forums are places for exchange and mutual assistance between WordPress users. If you have a question or a problem, you can post a message on the forum and get answers from the community.

It’s an excellent way to find solutions to specific problems and benefit from the experience of other users.

On Facebook, check out the Digital-Cookie group (in which your humble author of these lines is active).

Calling on a WordPress Professional for Personalised Assistance

If you’ve tried everything and the critical error persists, it may be wise to call on a WordPress professional. An experienced WordPress developer will be able to diagnose the problem in depth, identify the cause of this error and propose a tailor-made solution. This is precisely what our website maintenance and repair service covers, to prevent this kind of breakdown from happening again.

I’m not sending you to the competition — you can send me a message via the contact form, or ask Nova for a callback.

The Most Common WordPress Errors and How to Resolve Them

Knowing the most common errors is already doing half the work. Some critical errors are more frequent than others on WordPress sites. By familiarising yourself with this CMS, you will be better prepared to identify and resolve them quickly.

Bear in mind that everyone has been through it, and we always learn the hard way!