macOS Sierra is a fantastic update arriving from Apple to make us love our Macs even more. It has enough of new features, and as well has the aforementioned piece of cake clean install and upgrade flow equally did the previous Bone.

Acquire MORE: How to Clean Install the macOS Loftier Sierra?

Note, that getting an upgrade is the easiest way of installing the new macOS. Information technology saves all your personal files, apps and user data, while a and then-called clean install of Sierra will erase all data on the startup drive and replace it with a clean copy of OS. But, if you like an idea of giving your Mac a fresh start with a new macOS and nada else, a clean install is the right option for y'all.

Besides, in case you've noticed that with time your Mac is running slower, it has unusual startup or shutdown issues and crashes, a clean install may be a skillful way to become dorsum the speed and fix the problem.

Beginning of all, make sure that your Mac is able to run MacOS Sierra.

Then, you should prepare your Mac for the installation:

  • Download macOS Sierra Installer from the Mac App Store. One time the download completes, it will automatically launch. Quit macOS Sierra Installer app without performing the installation.
  • Accept a 16GB or larger USB wink drive to create a bootable Sierra installer. This flash drive is only needed for a make clean install on your Mac's startup drive. Only if you plan to clean install on a non-startup drive (you have and actress HDD or SSD on your Mac), y'all don't need the USB.
  • Fill-in your Mac to ensure your personal data is intact.
Download macOS Sierra from Mac App Store

Make clean Install macOS Sierra on Your Mac'due south Startup Drive

If you're going to perform a clean install on the startup drive, yous demand to backup your data, create a bootable copy of the installer, and, finally, boot from the bootable installer. So, allow us begin.

Stride 1: Clean up your Mac

To make sure Sierra has no troubles installing and works fine after, you demand to get rid of organization junk on your Mac showtime. You could clean it upwards manually, simply using a cleaning app like CleanMyMac Ten will save you hours on that. Junk removal with CleanMyMac takes only a few minutes. Download CleanMyMac for free, launch it, click Scan, and then Clean. Now yous've got plenty of complimentary space and your Mac is free from system trash.

Stride 2: Dorsum up your data

Note: A clean install of macOS Sierra on the startup drive completely erases all information on that drive: all your files and documents, including music, movies, pictures, and even apps.

So, If y'all skip this step, you wouldn't exist able to recover your data if something goes wrong.

To fill-in your Mac:

  • Open Fourth dimension Motorcar.
  • Click Select Disk.
  • Choose where y'all wish to save your files (to the external drive or to the cloud storage).
  • Click On to turn Fourth dimension Car on.
  • Click on the "pointer clock" icon and select Back up Now in the menu bar at the elevation of the screen.
Time Machine Backup

Step 3: Clean Install macOS Sierra on your startup disk

1. Create a bootable flash drive with macOS Sierra.

Showtime, make sure your USB wink drive is formatted and named every bit "Untitled".

  • To format a USB drive launch Disk Utility (Finder -> /Applications/Utilities/Disk Utility).
  • Select your USB drive nether External.
  • Click the Erase tab at the elevation of the Disk Utility window. Select Mac OS Extended (Journaled) from the format listing. Then, click the Erase button. When the procedure is consummate, click Done, and close the Disk Utility window.
  • If your drive is named something else, you lot need to rename it (Open Finder -> right click on the USB drive and choose Rename).

Now, your USB wink drive is ready.

  • Launch Last (Finder Applications Utilities Last)
  • Enter the following text into Terminal:
    sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resource/createinstallmedia --book /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app --nointeraction
  • Hitting the Enter fundamental.
  • Concluding volition ask you for an admin password (the one you use to log in). Information technology won't display characters when you lot blazon, so just practise information technology. Hit Return. Yous'll see that Terminal erases your drive. Then, Terminal volition copy the installer file to your disk. This volition accept a few minutes. When the process is complete, the Terminal window volition written report "Done." You can quit Last and your bootable macOS Sierra installer USB drive is prepare for apply.

Also, you can follow the instructions from an Apple tree article on how to create bootable installer.

2. Plug in the bootable macOS Sierra installer USB drive to your Mac.
3. Restart your Mac while holding the Option key or Cmd+R. Make sure to keep information technology pressed!
4. When Mac restarts, you'll come across the macOS Startup Manager with a listing of bootable devices that your Mac tin can outset upwards from.
five. Apply the arrow keys to choose your USB drive with macOS Sierra installer. Press Enter.
6. Select Disk Utility.
7. In the window, at the peak of the left bar, select your Mac's Principal Drive (it looks like a MacintoshHD).
8. Select the Erase tab located next to the First Aid button at the tiptop.
9. Well-nigh the eye of the window, select the Format drop-down list and select Mac OS X Extended (Journaled) type.
ten. Click Erase (Notation: this will erase all your data from your main drive!) and give the drive some time to format.
xi. When it's done, close Disk Utility and select "Install macOS" from the menu.
12. Select your primary drive and install the new macOS Sierra 10.12.

Follow these Sierra install instructions and enjoy your newly clean-installed macOS Sierra.

Clean Install on a Non-Startup Drive

This type of clean install doesn't crave you to make a bootable copy of the macOS installer, since yous can run the installer straight from your Mac'southward startup bulldoze. Simply you demand to have another hard drive or book that you can employ for installing macOS.

So, this is the easiest way to clean install macOS 10.12. Just utilize an extra drive or volume (it doesn't have to necessarily be empty already, y'all just need to be fine with information technology being erased) and install Sierra there.

Stride 1: Erase your non-startup drive

If your non-startup bulldoze has any other Mac Bone, erase information technology before installing Sierra. If the target drive but has personal information on it, or is already empty, you can skip the erase procedure.

To erase the non-startup drive, use a Mac's Drive Using Deejay Utility (Bone 10 El Capitan or afterwards)

Later on the non-startup drive is erased, you lot can offset the install process.

Step two: Download the macOS Sierra Installer from the Mac App Store

When the macOS download completes, it volition automatically launch the installer. Quit the macOS Sierra Installer app without performing the installation. You lot'll find the macOS Sierra Installer in the /Applications folder.

Step three: Start the Installation of macOS Sierra on the Non-startup drive

  • Launch the Installer from /Applications folder.
  • Click Continue.
  • Cheque the not-startup drive that you lot tin can install Sierra on (usually, the installer will brandish the default target for the installation of macOS Sierra every bit the startup drive (Macintosh HD). So, you should to click the Show All Disks button, and the installer will display a list of all attached volumes).
  • Click the Install push button.
  • The macOS Sierra installer will display a progress bar. You'll be guided through the macOS Sierra setup process to create a user account, set upwards appointment and fourth dimension, and other introductory stuff.

Relish your fresh, clean-installed macOS Sierra.