Why WordPress Websites Break After Updates: Common Causes and Solutions
Updating a WordPress website is one of the most important parts of keeping it secure and reliable. This includes not only the WordPress core, but also installed plugins and themes, all of which receive regular updates with security patches, bug fixes and performance improvements. These updates help the website stay stable and up to date with modern technologies. However, it’s not uncommon for a website to stop working immediately after clicking the “Update” button.
A broken layout, missing functionality, or even the dreaded white screen can be alarming, especially for business owners who rely on their website every day.
Fortunately, updates themselves are rarely the real problem. In fact, delaying updates for too long often creates a greater risk, as multiple major changes accumulate and compatibility issues become more difficult to identify. In most cases, the issue lies in how different parts of a WordPress website interact with each other.
Why WordPress Websites Break After Updates
A WordPress website is made up of several components that need to work together. The WordPress core provides the foundation, the theme controls the site’s appearance, plugins add extra functionality, and the server environment—including the PHP version and hosting configuration—keeps everything running. Because these components are often developed and updated independently, a change in one of them can sometimes affect the others.
Most update-related issues fall into a handful of common categories.
Plugin and Theme Compatibility Issues
The most common cause of website failures after an update is a compatibility conflict.
Updating WordPress can expose several types of compatibility issues. A plugin or theme may not yet support the latest WordPress version, two plugins that previously worked together may begin conflicting after one of them is updated, or a plugin may no longer work correctly with the active theme.
In each case, the result is similar: parts of the website stop working, error messages appear, or visitors may only see a blank page.
This doesn’t necessarily mean the plugin or theme is poorly developed. Because WordPress, plugins, and themes are developed independently, compatibility updates don’t always become available at the same time.
The more plugins a website uses, the more interactions there are between different pieces of software. While many websites run dozens of plugins without problems, each additional plugin slightly increases the chance of a compatibility issue after an update.
PHP Version Compatibility
WordPress, plugins, and themes are all written in PHP, so they depend on the PHP version running on the server. Different PHP versions introduce changes in performance, security, and internal behaviour, which means that not every WordPress installation, plugin, or theme will work correctly with every PHP version.
This can create a few different situations:
- WordPress is updated, but the server is still running an outdated PHP version.
- The hosting provider upgrades PHP, but an older plugin or theme is not compatible with it — or a plugin or theme is updated and no longer works with an older PHP version.
- The website is running an older version of WordPress, while the server is already using a newer PHP version that is not fully compatible with it.
Each scenario can cause parts of the website to stop working or trigger critical errors.
Cache Problems After Updates
Not every issue after an update is caused by the code itself.
Many websites use browser caching, server caching, or caching plugins to improve loading speed. After an update, visitors may still receive old cached files while the website is trying to load new scripts and styles.
This mismatch can result in:
- broken page layouts;
- missing styling;
- JavaScript errors;
- buttons or menus that no longer work correctly.
Since cache-related issues can look very similar to compatibility problems, they’re an important possibility to keep in mind when troubleshooting a website after an update.
Custom Code That Doesn’t Survive Updates
Updates require extra care if WordPress core files or theme files have been modified directly.
If someone has directly edited WordPress core files or modified a theme instead of using a child theme, those changes may be overwritten during an update. As a result, custom functionality disappears, layouts change unexpectedly, or parts of the website stop working altogether.
This is one reason why WordPress best practices recommend keeping custom code separate from the core installation whenever possible.
What to Do If Your Website Stops Working
If your website breaks after an update, avoid making multiple changes at once. A systematic approach makes it much easier to identify the actual cause.
Clear the Cache
Before assuming the update itself caused the problem, it’s worth checking whether you’re simply seeing an outdated version of the website. Cached files stored by your browser, a caching plugin, or the hosting provider can sometimes cause outdated scripts or styles to be loaded after an update. This may make the website appear broken even though the update completed successfully.
Start by clearing your browser cache and refreshing the page. If your website uses a caching plugin, clear its cache as well. Many hosting providers also offer server-side caching, which may need to be purged from the hosting control panel.
If the website starts working normally after the cache has been cleared, the issue was most likely caused by outdated cached files rather than a problem with WordPress, a plugin, or the theme itself.
Disable All Plugins
Plugin conflicts account for a large percentage of update-related problems.
If you suspect a particular plugin, start by temporarily deactivating it through the WordPress dashboard. If the website works normally afterwards, you’ve likely identified the source of the problem. If you can’t identify a likely culprit, try disabling all plugins and then reactivate them one at a time. This helps determine which plugin is causing the conflict.
If you can’t access the WordPress dashboard, you can disable all plugins by using your hosting file manager or FTP to temporarily rename the /wp-content/plugins/ folder (for example, to plugins-disabled). If the website starts working again, rename the folder back to plugins. WordPress will keep the plugins deactivated, allowing you to log in and reactivate them one at a time through the dashboard to identify which plugin is causing the problem.
If you can’t access the WordPress dashboard and already suspect a particular plugin, you can rename only that plugin’s folder inside /wp-content/plugins/. This deactivates only the selected plugin, allowing you to check whether the website starts working again without disabling all plugins.
If you’ve identified the plugin causing the problem, check whether a newer version is available, as the developer may already have released a compatibility update. If no update exists, you may need to keep the plugin disabled temporarily, replace it with an alternative, or contact the developer for guidance. For business-critical functionality, it’s also worth checking whether the plugin is actively maintained before continuing to rely on it.
Switch to a Default Theme
Themes can also become incompatible after major updates.
If you can access the WordPress dashboard, start by temporarily switching to a default WordPress theme. If the website starts working normally, the issue is likely related to the previous theme.
If you can’t access the dashboard, you can rename your active theme folder inside /wp-content/themes/ using your hosting file manager or FTP. WordPress will then look for another available theme and activate it automatically, provided a default theme is installed.
If the website loads normally afterward, the problem is likely related to the previous theme.
If the theme is responsible, check whether the developer has released a newer version that addresses the issue. If the problem is related to custom modifications, those changes may need to be updated to work with the latest version. If no compatible update is available, you may need to temporarily restore the previous version of the theme while the issue is resolved.
Check Error Messages
If an update results in a blank page or a critical error, checking the error messages can help identify the cause instead of relying only on trial and error.
WordPress includes a debugging mode that can reveal PHP errors hidden behind a blank screen. If you have access to the website files, debugging can be enabled temporarily in the wp-config.php file by changing:
define( 'WP_DEBUG', false );
to:
define( 'WP_DEBUG', true );
This allows WordPress to display errors, which can show whether the problem comes from a specific plugin, theme, or PHP file. However, displaying technical error messages publicly is not recommended on a live website, so debugging should only be enabled temporarily while investigating the issue.
In some cases, error details may be available in log files instead of being shown directly on the website. WordPress can store debugging information in a log file, and many hosting providers also provide server error logs through the hosting control panel. These logs can contain details about failed PHP processes, missing files, or other technical issues that help identify the cause of the problem.
If the issue affects only certain parts of the website rather than causing a complete failure, browser developer tools can provide additional clues:
- the Console tab shows JavaScript errors that may affect interactive elements, forms, menus, or other front-end functionality;
- the Network tab shows failed requests and can help identify files or scripts that are not loading correctly.
For website owners who aren’t familiar with technical diagnostics, sharing these error messages or logs with a developer can significantly reduce troubleshooting time because they usually point to the specific plugin, theme, file, or server setting causing the issue.
Check the PHP Version
Since WordPress, plugins, and themes depend on PHP, an update may expose compatibility issues with the PHP version running on the server.
Check which PHP version your hosting account is using and compare it with the requirements of your WordPress version, active theme, and important plugins. Hosting providers usually allow you to view or change the PHP version from the hosting control panel.
If you identify a PHP compatibility issue, compare the PHP requirements of your WordPress version, active theme, and installed plugins. Depending on the cause, the solution may be to update WordPress or the affected plugin or theme, or temporarily switch the server to a compatible PHP version while waiting for a permanent compatibility update. Older PHP versions should only be used as a temporary workaround, as they eventually stop receiving security updates.
Check Custom Modifications
If the website includes custom changes made directly to WordPress core files or theme files, check whether they were overwritten during the update.
This is especially important if someone has modified WordPress core files or edited theme files directly instead of using a child theme. Updates can replace these files with newer versions, causing previous customisations to disappear.
The solution depends on what was changed. If the update overwrote custom code, those modifications will usually need to be restored manually. To avoid the same problem in the future, custom functionality should be moved to a child theme, custom plugin, or another update-safe location rather than modifying WordPress core files or the parent theme directly.
Restore a Backup or Previous Version
If the problem cannot be resolved quickly and the website needs to be back online as soon as possible, restoring a recent backup or temporarily downgrading the affected component may be the best option. This gives you time to investigate the issue without leaving visitors with a broken website.
This approach is only possible if you have reliable backups. That’s why regular backups of both your website files and database are an essential part of WordPress maintenance. Ideally, a fresh backup should be created before every major update so you always have a safe recovery point if something goes wrong. If you’d like to learn more about creating and managing backups, see our guide to backing up your WordPress website.
How to Prevent Problems Before They Happen
While no update is completely risk-free, most failures can be avoided with good maintenance practices.
Some of the most effective precautions include:
- creating a full backup before every update;
- testing major updates on a staging copy of the website first;
- keeping WordPress, themes, plugins, and PHP versions appropriately updated;
- removing plugins that are no longer maintained;
- avoiding direct modifications to WordPress core files;
- monitoring plugin compatibility before installing major WordPress releases.
For business websites, online stores, and other mission-critical projects, regular maintenance is often a safer approach than applying updates only once or twice a year. Smaller, routine updates are generally easier to manage than catching up after months of neglected maintenance.
If you don’t have the time or technical expertise to manage updates yourself, a professional WordPress website maintenance service can help keep your website secure, updated, and running smoothly while reducing the risk of unexpected downtime.
Conclusion
WordPress updates are essential for security, performance, and long-term stability, but they can occasionally expose compatibility issues between plugins, themes, PHP versions, and custom code.
The good news is that most update-related problems are preventable. Regular backups, proper testing, and keeping every part of your website up to date greatly reduce the chances of a failed update.
With a proactive maintenance routine, you can benefit from the latest WordPress improvements without worrying that every update might take your website offline.
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