The drive will be reformatted automatically as part of the process. I’ve used different drives with success, including a VisionTek 120GB USB 3.0 Pocket Solid State Drive ($83 on Amazon) and an old 8GB Iomega Micro Mini Hard Drive.ĭon’t worry if the drive isn’t formatted for the Mac. You can use a USB flash drive or a hard drive with room for the installer software. If it automatically launches after download, quit the installer. Look for macOS Sierra in the list of apps that you’ve bought, and click on the Download button. You can download it again if you go to Purchased in the App Store. If you’ve already upgraded your Mac to Sierra, the installer is removed from the Applications folder. Keep the installer in the Applications folder.
