If you want to start over and wipe out the data, you need to go into Disk Utility to reformat the internal drive first, and then install macOS Sierra. If you want to install Sierra and leave the data intact, select Install OS X. Your Mac will display an OS X Utilites window.(You don’t need to select a network to proceed.) Click on the external drive and hit Return. After a few moments, your Mac should display the Startup Manager, which will show you the available boot drives.Press down on the Option key while the Mac boots. Plug your external drive into your Mac.You can quit Terminal and your drive is ready for use. You should see Terminal display a “Copy complete” and Done notice. Terminal will copy the installer file to your drive.When that part is done, your Mac may ask you if you want to use the drive for Time Machine. You’ll see that Terminal erases your drive.To confirm that you want to continue, type Y and hit Return.

Terminal will tell you that it will erase your drive.Terminal doesn’t display characters when you type it in. Go back to Terminal and paste the copied code at the prompt.Sudo /Applications/Install macOS Sierra.app/Contents/Resources/createinstallmedia -volume /Volumes/Untitled -applicationpath /Applications/Install macOS Sierra.app Launch Terminal (/Applications/Utilities/Terminal.app).If your drive is named something else, you need to change Untitled to the name of your drive.) (In the Terminal command you will use, I use Untitled to represent your external drive. Connect the external drive to your Mac.If your really don’t want to use Terminal, there are a couple of free apps you can use. The process detailed below involves the Terminal. Change the name of your drive to Untitled you need to do this for the steps below. 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.

Install mac os sierra from usb