Ubuntu lacks a system reset feature, requiring users to use a live USB for clean installations. It does not support repair upgrades using the latest ISO image. There is no system restore function, meaning users must perform full reinstalls to recover from issues. Ubuntu also lacks Optical Character Recognition (OCR) capabilities in its screenshot tool and image applications, forcing reliance on external solutions. Additionally, there is no seamless phone integration like Windows' Phone Link app, limiting productivity. Despite its user-friendly interface and package management, these missing features hinder Ubuntu's appeal as a leading Linux distribution.