An installation error occurs sometimes for when upgrading from OS X Snow Leopard to OS X Lion “Can't download the additional components. Do not attempt restoring macOS unless you are connected to the AC charger or have a fully charged battery. I assume your MBA is able to do. However, I tried again by dd 'ing the same disk image into my USB drive and it worked! more at home booting installation media from disc rather than USB, Worth noting is that Snow Leopard is the minimum required to. Install OS X OS X El Capitan Downloading additional components. Your computer will restart automatically. About , hours and 58 minutes remaining. In other words, sometimes the installation progress bar and time remaining indicator are wildly inaccurate when installing OS X Yosemite, but. It doesn't look right, but that depends on your Internet connection and your hardware so it's hard to tell in general. What are you downloading, system updates. An installation error occurs sometimes for when upgrading from OS X Snow Leopard to OS X Lion “Can't download the additional components. a brew command. Went to OS X Mountain Lion downloading additional components. Needed To Install Mac OS X. Hours to download additional components when reinstall. An alternative way to install macOS is to first download macOS High Sierra from the App Status: signed by a certificate trusted by Mac OS X Certificate Chain: 1. macOS Mojave and OS X High Sierra Hackintosh instructions, tutorials, step-by- step how to guides and installation videos; Hackintosh systems, parts and more.