Enable WordPress debug log safely

When to use this guide

Use this when WordPress returns a 500 error, shows a white screen, breaks after a plugin or theme update, or hides the PHP error you need to diagnose.

Safety notes

• Add debug constants above the line that says to stop editing.
• Keep WP_DEBUG_DISPLAY off on public sites.
• Remove or disable temporary debug settings after the incident is understood.
• Do not paste full debug logs publicly if they include paths, usernames, tokens, or customer data.

Basic steps

Add or update these constants in wp-config.php:

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

Then reload the failing page once and check wp-content/debug.log.

Expected result

The site should not display raw PHP errors to visitors. The debug log should capture fatal errors, warnings, plugin paths, theme paths, or missing PHP extensions that point to the next repair.

Next links

• If the log names a plugin, use Disable plugins in WordPress without admin access.
• If the log stays empty, compare server logs with Check access and error logs for HTTP failures.
• If the failure follows a change, use Roll back a website change safely.