Fix the WordPress White Screen of Death

WordPress shows a blank white page with no error message (HTTP 500)

Common causes

• A plugin or theme update with a PHP fatal error or incompatibility with your PHP version
• PHP memory limit exhausted
• A syntax error after editing functions.php or wp-config.php
• Corrupted or partially uploaded core, plugin or theme files
• An outdated drop-in such as object-cache.php or advanced-cache.php
• Server-side caching serving an empty cached response

How to fix it

1. Enable the debug log. In wp-config.php, above the line /* That's all, stop editing! */, set WP_DEBUG and WP_DEBUG_LOG to true and WP_DEBUG_DISPLAY to false. Reload the page, then read wp-content/debug.log for the PHP Fatal error line.
2. Check the server error log. If debug.log stays empty, look at the PHP or web server log, for example /var/log/nginx/error.log, /var/log/apache2/error.log or the hosting panel's error log. Errors very early in loading often only appear there.
3. Disable the plugin that failed. Over SFTP or the file manager, rename the plugin folder from the log, such as wp-content/plugins/plugin-name to plugin-name.off. If you do not know which plugin, rename wp-content/plugins to plugins.off to disable all of them, then restore and re-enable one by one.
4. Switch to a default theme. If the error points to your theme, rename its folder in wp-content/themes. WordPress falls back to an installed default theme such as Twenty Twenty-Four; with WP-CLI run wp theme activate twentytwentyfour.
5. Raise the memory limit. If the log shows Allowed memory size exhausted, add define('WP_MEMORY_LIMIT', '256M'); to wp-config.php and make sure PHP's memory_limit is at least as high.
6. Replace core files and clear caches. Re-upload fresh wp-admin and wp-includes folders from wordpress.org (or run wp core download --skip-content --force), then purge the page cache, CDN and any object cache.

wp-config.php

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );      // writes to wp-content/debug.log
define( 'WP_DEBUG_DISPLAY', false ); // keep errors off the page
@ini_set( 'display_errors', 0 );

How to stop it happening again

• Test plugin, theme and PHP version updates on a staging site first
• Keep automatic backups you can restore from outside wp-admin
• Edit theme files over SFTP or Git rather than the built-in file editor
• Turn WP_DEBUG off again after fixing so debug.log does not grow or leak information