Magento 1.9 SUPEE-10415 Causing Product Pages not Found 404 Error: How to Fix

Magento 1.9.x SUPEE-10415 Known issue Issue: Magento 1.9.x displays a “404: Page Not Found” error from the errors/ directory after upgrading to SUPEE-10415. This issue occurs only in Magento installations that run certain third-party extensions. Magento 1.9.3.6 and later with SUPEE-10415 contain a potentially serious bug. Under certain conditions, every… Read More