WordPress white screen after update: what I check first

I get this ping a lot. Yesterday the site was fine. Today it is a blank white page, or a "There has been a critical error" notice, right after someone hit Update. Store owners and agencies both hit it. The fix is usually boring once you stop guessing.

Here is how I chase a WordPress white screen without making production worse.

Note what changed in the last day

Before you click anything else, write down the last change. WordPress core, a plugin batch, a theme update, a PHP version bump on the host, or a caching flush. That short list is your suspect sheet. More updates on a broken site are the wrong next step.

Turn on the real error for a minute

A white screen hides the fatal. On staging (or briefly on production if you have no staging), enable WP_DEBUG and WP_DEBUG_LOG so the error lands in wp-content/debug.log. Read the last fatal. A missing class after a plugin update, a PHP version mismatch, or a theme function that no longer exists will usually show up there.

Check hosting and PHP first

• PHP version changed overnight and an old plugin cannot run
• Memory limit too low after a heavy plugin update
• Disk full so WordPress cannot write sessions or cache
• CDN or page cache still serving a broken response

If the host panel shows a PHP error or a failed deployment note, start there before you dismantle the plugin list.

Isolate plugins and theme safely

Prefer staging. If you only have live, rename the plugins folder via SFTP or the host file manager so WordPress loads with none active, then rename it back and reactivate in small groups. Same idea for a custom theme: switch to a default theme briefly to see if the fatal is theme-side. Keep a note of what you changed so you can reverse it.

Do not clear everything at once

Clearing every cache, flipping PHP versions, and mass-updating plugins in one panic session mixes the signals. Change one thing, reload, check the log. If checkout or admin still loads while the front is blank, look at page builders, security plugins that rewrite front requests, and object cache.

When to call someone in

If you have already spent an hour renaming folders with no clear fatal in the log, stop. Downtime costs orders and leads. I keep a short path for this kind of rescue on WordPress and WooCommerce support.

Fix the actual fatal, then test updates on staging next time. That habit saves more weekends than any "optimisation" plugin ever has.