In Disk Utility, select your USB drive from the list on the left. You can find Disk Utility by searching for it in Spotlight or in Applications > Utilities. With your USB drive connected to your Mac, launch the Disk Utility app. The process of creating the USB installer deletes all data on the USB drive, so make sure it doesn’t contain any important files. To create a macOS Sierra USB installer, you’ll need a USB 2.0 or USB 3.0 drive with a capacity of at least 8GB. You can quit the installer application by using the keyboard shortcut Command-Q. Quit the install application, as this is meant for users who wish to upgrade their Macs to Sierra, not create a USB installer. Once it has completed the download, the Sierra installer will automatically launch. Using a compatible Mac, simply launch the App Store, find Sierra from the homepage sidebar, and download the installer.
To create a USB installer for macOS Sierra, you first need to download the installation application from the Mac App Store.
Step 1: Download macOS Sierra from the Mac App Store
