If you want the ability to perform a fresh and clean install of macOS High Sierra, then you should consider creating a bootable macOS High Sierra USB install drive. Follow these steps to create a bootable USB installer drive for macOS High Sierra to deploy Apple’s latest OS on supported computers.
Requirements for creating a bootable drive
- 8 GB USB flash drive (or SD card)
- Install MacOS High Sierra.app (the installer downloaded from the Mac App Store)
- Apple computer with Mac App Store (OS X 10.7.5 or later)
- User account with administrative privileges
Create a bootable USB installer for macOS High Sierra
Step 1: Download macOS High Sierra from the Mac App Store.
Step 2: Once macOS High Sierra is downloaded, close the installer that appears using Command (⌘)+Q.
Step 3: Open Finder → Applications and right-click on Install macOS High Sierra Beta and select Show Package Contents.
Step 4: Open Contents → Resources.
Step 5: Open a macOS Terminal window via Applications → Utilities → Terminal.
Step 6: In the Terminal window type sudo followed by a space.
Step 7: Drag createinstallmedia into the Terminal window from the Finder location opened in Step 4.
Step 8: Type
--volume followed by a space.
Step 9: Connect your USB drive to your Mac.
Step 10: Drag the USB flash drive volume into the Terminal window.
Step 11: Type
--applicationpath in the Terminal window followed by a space.
Step 12: Open Finder → Applications and drag Install macOS High Sierra Beta into the Terminal window.
Step 13: Press Return on the Keyboard to submit the full command.
Step 14: Type a ‘Y’ to continue when prompted to do so, and press Return on the keyboard.
Step 15: The install process will commence by erasing the contents of your USB drive and copying the installer files to the drive. The process should only take a few minutes, depending on your computer’s specifications. Once the process completes successfully, an on-screen confirmation will be displayed as confirmation that the drive is ready for use.
Using the newly created USB installer, users are able to upgrade to macOS High Sierra directly from an existing installation of macOS or OS X; otherwise, a clean install may be performed by inserting the drive to an available USB port and powering on the computer while pressing down the Option key. This invokes the boot selection menu from where users can boot to the USB drive and follow the prompts to install macOS High Sierra on the Mac.