How to Clean Install macOS: All You Need to Know

When you decide to download and install the latest macOS, you find yourself surrounded by numerous possibilities and the need of some of the most required cleanups. Also, if you prefer to begin with a fresh MacOS installation, you can simply make a clean install. And if you are unaware of the process on how to clean install macOS, you may find difficulties while executing the same.

Therefore, in this article, we have come along with some of the most important factors that will help you to have a completely clean install of your macOS with ease. Besides, we will be discussing the various circumstances that are of much significance before you move to the clean installation process of MacOS.

What do You Need to Clean Install MacOS?

There are some factors that go on before you clean install macOS. So, before you begin with the clean installation process of MacOs, we want you to be familiar with all the factors. Besides, it will be easier for you to execute the clean install process off macOS in your device. Hence, we suggest you go through the steps listed below.

  1. The very first thing which is significantly important to have with you is a 15GB or more removable USB flash drive. You will require this to keep the installer file for your preferred version of MacOS. Here, note that the USB drive is necessarily advised for the clean install of the startup of Mac. Moreover, if you do not want to clean install macOS, then you don’t need to have it with you.
  2. Also, you are on the verge of removing the entire files from your device, so, make sure that you backup all your important data before proceeding to that. And for that, you might require the admin privileges already.
  3. Another important thing includes the macOS High Sierra Installer and you can easily get it from the Mac App Store.
  4. Apart from that, the complete process takes a little longer time and you should have at least an hour or maybe two, arranged for the clean install process.

Method 1: Clean Install macOS on a Startup Drive

When you are done with all the previously recommended stuff, you can start with the clean installation of macOS. You can clean install your macOS on a startup drive and for that, you need to follow these steps:

Start with a System Cleanup

To begin with the process, first, you will require to start with a simple system cleanup. Here, you need to remove all the data present in your device that is of least significance to you. All the unnecessary files, large and obsolete data, faulty applications, cache portions, junk files, duplicate folders, and all that is not required is suggested to be removed.

Step 1: Backup All Your Important Data

Apart from the system cleanup, it is really important that you backup all your important files before you clean install macOS on a startup drive. For that, you can use the backup application to store your significant files in a safe place. Also, you can create bootable clone so that you can get back all the important files that you might lose during the process. Better yet, it comes along with a clone drive which helps you generate a duplicate file in your recently upgraded system. Therefore, you can easily move or transfer all of your important images along with the documents in safe cloud storage. Apart from that, you can prepare a safe backup of your Mac as well. Moreover, you have to ensure that you hold a complete history of license codes for the applications and passwords for the specific websites that you indulge in.

Step 2: Create a Bootable macOS Installer

Also, you need to create a bootable macOS installer in this method. For that, we recommend you to follow these steps:

  1. First, you need to download the macOS High Sierra from the App Store.
  2. Then, you can move to the File and Quit option.
  3. Next, you will require to plug in the USB stick. And then, you can launch the Disk Utilities.
  4. After that, you need to tap on the Erase tab.
  5. Rename your USB stick and then you can proceed with the Erase option.
  6. Now, launch the Terminal.
  7. Then, you have to type in the following command.

sudo /Applications/Install\ macOS\ High\ –volume /Volumes/[YOUR DRIVE NAME] –application path /Applications/Install\ macOS\ High\

  1. Then, you can click on the Return option. Besides, you have to provide the admin password and wait for a moment.
  2. Finally, you can quit the Terminal.

Method 2: Install macOS on your Startup Disk Drive

This is the second method on how to clean install macOS. Here also, you first need to back up your Mac so that you can keep all your important files at a safe location. So, if you are unaware of the process on how to erase your Mac’s main drive, you can follow the steps right below.

  1. To begin with the process, you will require to go to the System Preferences.
  2. Then, you have to select the Startup disk option. Also, you will require to open the installer that you have recently generated in your device.
  3. Next, you need to restart your Mac device. Then, you have to boot your device into the recovery mode.
  4. Now, you can use your bootable USB to make a connection to it with your Mac device.

After that, you will need to wait for a moment when you get to see the macOS Utilities appearing on the screen. Then, you can proceed with the following steps.


  1. To begin with, you will require to click on the Reinstall button. This will provide you with the latest copy of macOS.
  2. Then, you can tap on the Continue option. Next, you need to proceed with another Continue option in the window which appears next.
  3. Now, you have to click on the Agree to the terms and conditions. And then, you need to choose your Mac’s internal drive.
  4. After that, you will require to tap on the Install option.
  5. Here, your macOS High Sierra will take a moment to complete the installation process. Then, you can restart your Mac.
  6. After the reset process, you will require an entirely new setup of your Mac. For that, you can connect your device to the WiFi connection and provide the user password. Besides, the system will ask you for more information. You can type in all the necessary details and then set up a new user account.

Method 3: Clean Install macOS High Sierra on a Non-startup Drive

Here is another method on how to clean install macOS which you need to follow. Also, you don’t require any back up during this process. Better yet, this particular method is proved to be more safe and convenient for most users. The only thing that you require to have here is an extra drive. So, we recommend you to follow these steps to install the latest macOS on a non-startup drive.

Step 1: Remove your Non-startup Drive

This is the very first step that you have to start with. So, before you install the latest macOS in your Mac device, you will require to remove all the data that currently use your drive. And for that, you can make use of the Disk Utility. Further, you can select the volume and then you need to tap on the Erase button.

Step 2: Download the macOS High Sierra Installer from the Mac App Store

Now, this is the second step on how to clean install macOS High Sierra on a non-startup drive. In this step, you need to download the macOS High Sierra Installer from the Mac App Store. , And for that, you need to follow these steps.

  1. Initially, you need to go to the Mac App Store. There, you have to navigate to the Updates tab.
  2. Next, you can download and launch the installer automatically. Also, note that you will require to quit it as well.
  3. Now, you can run the installer using the start-up drive. With this, you can install the macOS successfully. Besides, you do not require any particular bootable drive here.

Step 3: Install macOS High Sierra to your Non-Startup Drive

Now, you will require to install macOS High Sierra to your non-startup drive. And for that, you can follow these steps.

  1. To start with the process, you first need to launch the installer using the applications folder.
  2. Then, you can proceed with the Continue option.
  3. Now, you have to alter the target drive for installation.
  4. After that, you can see a macOS startup drive. Here, you need to select the Show All Disks button.
  5. Then, you can select your preferred startup disk volume.
  6. Next, you need to follow the installation guide.
  7. Set up your Mac device as a new one.
  8. Here, you have to generate your new user account for the Mac device.
  9. After that, you will require a complete setup of your new user account. Along with that, make sure you set up the date and time zone as well.

Frequently Asked Questions

These are some of the most frequently asked questions that you should have a look at:

1) How do I wipe my Mac and reinstall?

You can select your startup drive and then switch to the Erase option. Then, move to the Mac OS Extended. After that, you need to click on the Format drop-down menu. Proceed with the Erase option. Next, you need to quit out of the Disk Utility app. Then, click on the Reinstall option and you are done!

2) How do you clear everything off a Mac?

Start with the command key and R key and then you can move to the MacOS Utilities. Next, you need to click on the Disk Utility option. Under the hard drive option, you need to select the Erase button. After that, navigate to the Mac OS X Extended and then, click on Erase.



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