PrestaShop 500 Error: The Checklist to Get Your Store Back Online in Under an Hour

Every Hour of Downtime Costs You Money

A PrestaShop store generating €3,000 in daily revenue loses around €125 for every hour it is down. The priority is not to understand the issue—it is to get the store back online first, then investigate the cause.

1. Enable Debug Mode (2 Minutes)

In config/defines.inc.php, set _PS_MODE_DEV_ to true while you troubleshoot. The 500 error will be replaced by a specific message: missing class, insufficient memory, or SQL error.

2. Check the Actual Logs

Check these three locations, in this order:

• var/logs/ (PrestaShop 1.7 / 8)
• your hosting provider's PHP error log
• error_log in the site's root directory

3. The Five Most Common Causes We See

1. A newly installed module breaking a hook.
2. A conflicting override after an update.
3. A memory_limit that is too low for a catalogue import.
4. A corrupted Smarty cache: clear var/cache/.
5. A PHP migration (8.1 → 8.2) running outdated code.

4. Restore a Stable Version

Disable the faulty module directly in the database (ps_module, active column), clear the cache, and test the store. This gets your store back online—the permanent fix comes next.

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