How to Clean Install macOS Sierra

You can perform a clean installation of macOS Sierra to give your computer a fresh start. Unlike an upgrade, installing Sierra from scratch can iron out issues like quirky drivers, sluggish performance, and unnecessary hard drive bloat....

Part 1 of 3:

Preparing to Install Sierra

  1. Picture 1 of How to Clean Install macOS Sierra
    Make sure macOS Sierra can run on your Mac. Open the Apple menu and select 'About this Mac.' You should see something like 'MacBook Pro (13-inch, Early 2015) just beneath the operating version number. The following Mac systems are compatible with Sierra:[1]
    1. iMac (Late 2009 and newer)
    2. MacBook Air (2010 and newer)
    3. MacBook (Late 2009 and newer)
    4. Mac Mini (2010 and newer)
    5. MacBook Pro (2010 and newer)
    6. Mac Pro (2010 and newer)
  2. Picture 2 of How to Clean Install macOS Sierra
    Get a USB drive. Doing a clean install requires creating a bootable installation drive, so you'll need to have one ready. The drive can be any sort of hard drive (including a flash drive), and should have a minimum of 16GB of disk space.[2]
    1. The drive will be erased and reformatted by the installer, so be sure to back up your data.
    2. It's okay if the drive is not formatted for macOS.
  3. Picture 3 of How to Clean Install macOS Sierra
    Back up your Mac. Doing a clean installation of macOS Sierra will wipe your hard drive. Use the backup method of your choice to preserve your personal files, such as photos and documents.
Part 2 of 3:

Creating a Bootable Install Drive

  1. Picture 4 of How to Clean Install macOS Sierra
    Go to https://support.apple.com/en-us/HT208202
  2. Picture 5 of How to Clean Install macOS Sierra
    Click on Download macOS Sierra. A file named InstallOS.dmg will download.
  3. Picture 6 of How to Clean Install macOS Sierra
    Picture 7 of How to Clean Install macOS Sierra
    Picture 8 of How to Clean Install macOS Sierra
    Picture 9 of How to Clean Install macOS Sierra
    After the .dmg file has downloaded, open it, then click on InstallOS.pkg, and follow the onscreen instructions.
  4. Picture 10 of How to Clean Install macOS Sierra
    You will find the installer in the Applications folder.
  5. Picture 11 of How to Clean Install macOS Sierra
    Plug the USB drive to the computer. You'll see a hard drive icon appear on the desktop when the drive mounts.
  6. Picture 12 of How to Clean Install macOS Sierra
    Rename the USB drive. To make the drive easier to work with, name it 'bootdrive.'
    1. Right-click or Ctrl+click the drive icon.
    2. Select 'Rename.'
    3. Type bootdrive
    4. Press Return
  7. Picture 13 of How to Clean Install macOS Sierra
    Launch Applications > Utilities > Terminal.app. A black window with white text prompt will appear.
  8. Picture 14 of How to Clean Install macOS Sierra
    Copy the following command. Use your mouse to highlight the following (lengthy) command, then press Cmd+C to copy.
    1. sudo /Applications/Install macOS Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/bootdrive --applicationpath /Applications/Install macOS Sierra.app
  9. Picture 15 of How to Clean Install macOS Sierra
    Return to Terminal and press Cmd+V. The long code you copied will appear after the prompt.
  10. Picture 16 of How to Clean Install macOS Sierra
    Hit Return. Now you should see 'Password' on the next line in the terminal.
  11. Picture 17 of How to Clean Install macOS Sierra
    Type the administrator password and press Return. When the password is accepted, you'll see a message asking you to confirm that you want to erase the disk.
  12. Picture 18 of How to Clean Install macOS Sierra
    Press Y and then Return. The bootable version of the Sierra installer will start copying to your USB drive.[3]
    1. The process will take several minutes and you'll know it's complete when you see 'Copy Complete' and 'Done' in the terminal.
    2. If you see a pop-up message about Time Machine during the installation, click the 'Don't Use' button.
Part 3 of 3:

Installing Sierra from the Boot Drive

  1. Picture 19 of How to Clean Install macOS Sierra
    Click the Apple menu and select 'Restart.' A pop-up will appear asking you to confirm that you want to restart the computer.
  2. Picture 20 of How to Clean Install macOS Sierra
    Click 'Restart' on the confirmation window. The computer will power down and restart. Don't walk away from the computer, though! You'll need to take action as soon as it turns back on.
  3. Picture 21 of How to Clean Install macOS Sierra
    Hold down Option when you hear the reboot tone. After a few seconds you'll see a list of bootable drives connected to your Mac.[4]
  4. Picture 22 of How to Clean Install macOS Sierra
    Click 'Install macOS Sierra' and press Return. The macOS Utilities window will appear, containing a list of options.[5]
  5. Picture 23 of How to Clean Install macOS Sierra
    Select 'Disk Utility' and click Continue. Now you'll see a screen that looks similar to Finder. The left side contains a list of drives connected to the computer.
  6. Picture 24 of How to Clean Install macOS Sierra
    Click your startup drive on the left pane. You may have to expand the Internal section to find it. When you click the drive, its properties will appear in the center pane.
  7. Picture 25 of How to Clean Install macOS Sierra
    Click the 'Erase' button. It's located on the top toolbar. After clicking, you'll see a pop-up asking you to set some parameters.
    1. Remember, erasing the hard drive is permanent. Make sure you have backups.
  8. Picture 26 of How to Clean Install macOS Sierra
    Select 'Mac OS Extended (Journaled)' in the Formatting dropdown. This is the only parameter you'll need to change.[6]
  9. Picture 27 of How to Clean Install macOS Sierra
    Click Erase to confirm. The utility will now format your hard drive, which may take several minutes. You'll see a confirmation message once the drive has finished formatting.[7]
  10. Picture 28 of How to Clean Install macOS Sierra
    Close the Disk Utility window. This will bring you back to the macOS Utilities screen.
  11. Picture 29 of How to Clean Install macOS Sierra
    Select 'Install macOS' and click Continue. Now you'll be prompted to select a drive on which you'll install Sierra.
  12. Picture 30 of How to Clean Install macOS Sierra
    Click your freshly-erased hard drive. For most people, it's the only drive in the computer (and in most cases, it's called 'Macintosh HD').
  13. Picture 31 of How to Clean Install macOS Sierra
    Click the 'Install' icon. The icon is at the bottom of the window. Once clicked, macOS Sierra will install on your Mac. When the process is complete, your computer will boot to your brand new macOS Sierra desktop.
Update 04 March 2020
Category

System

Mac OS X

Hardware

Game

Tech info

Technology

Science

Life

Application

Electric

Program

Mobile