By Christian Fillion E-Commerce Strategist & Founder, Marketing Media
It is the most terrifying color in e-commerce: White.
You type in your URL. You hit enter. And you see… nothing. No error message. No logo. Just a blank white page.
This is the infamous “White Screen of Death” (WSOD). In technical terms, it is an HTTP 500 Internal Server Error.
If this happened recently, there is a 90% chance it wasn’t a hacker. It wasn’t a virus. It was likely a PHP Upgrade.
Your server just started speaking a new language, and your PrestaShop store doesn’t understand a word of it.
PrestaShop runs on PHP, a programming language. Like any language, PHP evolves. Words (functions) that were used in 2018 are considered “deprecated” (obsolete) in 2024.
You might be angry at your host. Don’t be. They are trying to protect you. Old versions of PHP (5.6, 7.0, 7.2) have known security holes. If a host keeps them running, they put their entire network at risk. They force these upgrades to prevent mass hacking events.
But they don’t know (or care) that your specific PrestaShop theme hasn’t been updated since 2019.
If you are staring at a white screen right now, don’t panic. You likely haven’t lost any data. The database is fine; the code just can’t display it.
Step 1: Turn on the Lights (Debug Mode) A white screen is useless. We need to see the error. We go into your server files (config/defines.inc.php) and change _PS_MODE_DEV_ from false to true. Suddenly, the white page vanishes, and a complex error message appears:
Fatal Error: Uncaught Error: Call to undefined function… Now we know exactly which module caused the crash.
Step 2: The Rollback The fastest way to get online is to revert the server environment. We log into your cPanel and downgrade the PHP version back to what your store supports (e.g., from 8.1 back to 7.4). Note: This is a temporary band-aid, not a cure.
You cannot stay on old PHP forever. Eventually, even the “Rollback” option will disappear. You have two choices:
A White Screen of Death stops revenue instantly. But worse, if Google crawls your site while it is white, it will de-index your pages.
If your site is down, or if you are terrified of the next server update, call us.
We can bridge the language gap and keep your store speaking clearly.
Download our [5-Point Profitability Audit] to check your PHP compatibility, or schedule an Emergency Repair below.