My theme broke after a PrestaShop update.

This happens when the update introduces changes that your theme is not prepared for. Steps: (1) Switch to the default theme temporarily (Classic or Hummingbird) to confirm it is a theme issue. (2) Check if your theme developer has released an update compatible with the new PrestaShop version. (3) If using a child theme, check which template files need updating. (4) If the theme is discontinued, you may need to migrate to a different theme — a painful but sometimes necessary process. Never update PrestaShop without checking theme compatibility first.

Learn more: PrestaShop child themes guide.