Clean install of macOS

Creating a bootable USB install disk

NOTE: If updating to High Sierra (10.13) or newer you must be using macOS 10.12.5 or newer.
  • Download macOS Mojave from the App store
  • When download finishes, quit the "Install macOS Mojave" app (i.e. do not press "Continue")
  • Format a USB drive, "Untitled", Mac OS Extended (Journaled), GUID Partition Map
Run the following command from a terminal:
sudo /Applications/Install\ macOS\ --volume /Volumes/Untitled --nointeraction
NOTE: If updating to High Sierra (10.13) or older you must also provide the applicationpath e.g.: --applicationpath /Applications/Install\ macOS\ High\

Wiping Mac followed by a clean install of macOS

  • Turn off Mac and insert bootable USB install disk
  • Hold down the Option key (alt key, ⌥) and start Mac
  • Choose the USB drive that says "Install macOS Mojave"
  • Select "Disk Utility", select main internal hard drive (Macintosh HD), press "Erase"
  • Name: "Macintosh HD", Format: "Mac OS Extended (Journaled)"
  • Close "Disk Utility" and choose "Install macOS"
  • Select internal hard drive (Macintosh HD) when prompted and continue with installation