Don Box, Meta's VP of Engineering and head of augmented reality software, is stepping down for personal reasons. His departure raises concerns about Meta's progress on its AR glasses project, including the development of a custom operating system. Meta plans to deliver a first generation of AR glasses by next year for internal use and select developers, with consumer shipping targeted for 2027. Despite this, Meta's CTO Andrew Bosworth has acknowledged challenges in bringing AR products to market. Meta has also faced difficulties in building custom silicon for AR/VR products, leading to layoffs in its Reality Labs custom silicon unit FAST last month.