How Do I Read and Understand a WooCommerce Error Log?

How to Read a Log Effectively

PHP error logs record entries chronologically, and a single root cause often triggers a cascade — a fatal error partway through a request can leave the system in an inconsistent state, causing later code (still trying to run) to throw its own additional errors that are symptoms, not separate problems. Working backward from the last log entry, rather than starting from the first fatal error, is a common mistake that leads to chasing symptoms instead of the actual cause.

What to Look For

• The word "Fatal error" specifically, since this is what actually stops execution — warnings and notices are often benign or pre-existing and rarely the reason for a broken page on their own.
• The file path and line number included with the error, which tells you exactly which plugin, theme, or core file the issue originates from.
• The timestamp to correlate the error with a specific action (a checkout attempt, an admin action) if you're trying to reproduce a specific reported issue.
• The first occurrence chronologically if multiple similar-looking fatal errors appear, since later ones may just be the same root issue recurring on different requests.
• Deprecated function notices, while not fatal themselves, are worth noting as a sign a plugin or theme needs updating, especially relevant after a PHP version upgrade.

Practical Steps

1. Enable WP_DEBUG_LOG in wp-config.php if not already active, and locate wp-content/debug.log.
2. Reproduce the specific issue and note the timestamp, then find the corresponding log entries around that time.
3. Identify the first fatal error in that sequence, and trace it to the specific file and plugin/theme it belongs to.
4. Turn off debug logging once the issue is resolved, since leaving it running indefinitely on a live site can accumulate a large log file and isn't necessary long-term.

Need help interpreting a confusing error log? See WooCommerce fixes.