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
