WordPress white screen of death

Symptoms

The front page, the dashboard, or the whole site renders as a blank white page with no error message. A partial white screen, where the admin works but the front end is blank, is a variant with a different cause list. The key fact: WordPress hid the error. Your job is to reveal it.

Common causes

• A PHP fatal error from a plugin or theme. The white screen is the browser showing the failed render.
• Memory exhaustion. A plugin or theme asks for more memory than WP_MEMORY_LIMIT allows, and the fatal error kills the render.
• A theme's functions.php with a typo, a missing function, or a call that dies.
• A corrupted plugin, a half-installed update, or an incompatible plugin after a core update.
• A bad autoload path in a mu-plugin or an added require in a config file.
• Blocked direct access to PHP files and an error report that is hidden, so nothing prints.
• PHP version changed on the host and code from an older error level now fatal.

How to fix

1. Turn on debugging. Add to wp-config.php, just before "That's all, stop editing":

define('WP_DEBUG', true); define('WP_DEBUG_LOG', true); define('WP_DEBUG_DISPLAY', false);

The error lands in wp-content/debug.log. Read the last lines. Remove the lines after you finish.

1. If the log stays empty, look at error_log or the host's PHP error log. Same event, different file.
2. Bump the memory limit on a dev copy first:

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

If the white screen goes away, something was memory-hungry and you can find the real fix later.

1. Isolate the theme. Rename the theme folder from inside wp-content/themes/, for example twentytwentyfour to twentytwentyfour_off. WordPress falls back to a default theme. If the screen recovers, the theme is at fault.
2. Isolate plugins. Rename the wp-content/plugins/ folder to plugins_off to disable all of them at once. Re-enable in halves to find the offender fast.
3. Check the recent core update. If the white screen started after an update, reinstall WordPress core from the host's one-click tool, then re-apply your custom code.
4. Clear caching layers: object cache, page cache, and CDN. A stale cached partial can look like a white screen.
5. Test on the server, not the browser cache. Use a private window and check the raw response with curl to prove the blank output is coming from the server.

Prevention

• Use a staging copy for every core, theme, and plugin update.
• Set WP_DEBUG_LOG true and WP_DEBUG_DISPLAY false permanently on production, and rotate debug.log so it stays small.
• Back up before updates, including database and files, so a release is one-click reversible.