Buzz
In this article, Mytour will guide you through the process of performing a clean installation of macOS, which is quite similar to wiping and reinstalling macOS. Please note that this article specifically focuses on clean installing macOS Mojave, but you can also apply it to clean install other versions such as macOS High Sierra, Sierra, El Capitan, Mojave, Yosemite, or even some older versions of Mac OS X.
How to Perform a Clean Installation of macOS
Preparing Your USB Drive
To install macOS, your USB drive must be formatted as a Mac OS Extended (Journaled) partition.
To format your USB drive, go to Applications => Utilities and open Disk Utility.
Select your USB drive and click Erase (make sure the USB drive is named Untitled).
In the Format section, select Mac OS Extended (Journaled).
If your Mac uses the APFS file system (if running macOS High Sierra or Mojave), simply choose APFS from the options list.
If available, under Scheme options, select GUID Partition Map, then click Erase =>Done.
Download the Mojave installation file
If you're simply reinstalling the latest macOS version, the steps are much simpler. Just head to the Mac App Store, search for the latest macOS version (in this guide, it's macOS Mojave).
Click on Download or Get (depending on your Mac App Store version) to initiate the installation file download.
You'll receive a notification on your screen indicating that this macOS version is ready to install and will ask if you'd like to proceed. Your task is to click on Continue, then input your Apple ID and password to proceed.
Note: The installation file size is quite large, specifically, the Mojave installation file is around 5.7GB, so the download process may take a considerable amount of time.
Once the download process is complete, the installer will automatically launch. Press Command + Q to exit the installer.
Next, locate the installation file (it will be in the Applications folder, or you can search via Spotlight by pressing Command + Space, typing Mojave in the Search bar, and hitting Enter).
If you're installing macOS Mojave, you can skip the instructions for downloading installation files for older Mac OS X versions below.
Downloading installation files for older Mac OS X versions
For older Mac OS X versions, downloading installation files can be challenging as Apple doesn't provide installation files for old OS versions on the Mac App Store.
However, you may find installation files for some older macOS versions in the Purchased section on the App Store. Log in to the Mac App Store with your Apple ID, then click on Purchased from the menu at the top corner.
Scroll through the list of apps you've purchased or downloaded for free to find the older Mac OS X versions you wish to install, then click on Download to initiate the download process.
However, this method also has some limitations, and it may not be effective:
- If you've installed Mojave on your Mac, you can't download older Mac OS X versions from the Mac App Store.
- If you're running macOS High Sierra, you can't download the version via the App Store.
- Additionally, you may not find the macOS version you've purchased in the Purchased section on the App Store.
- Lastly, you definitely won't find the macOS version in the Purchased section if you've never installed that version.
Create a Bootable USB Drive
The next step is to create a Bootable USB Drive to install macOS on your Mac from the USB drive. In the guide below, Mytour will instruct you on how to create a Bootable USB Drive using Terminal.
Insert your USB drive into your Mac, and make sure the USB drive name is Untitled; if not, you'll need to rename it.
Creating a Bootable USB Drive via Terminal
To open the Terminal application on Mac, press Command + Space and type the keyword terminal into the search bar.
Next, copy and paste the command line below into the Terminal window:
sudo /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled -- /Applications/Install macOS Mojave.app
Press Return, then enter your password.
Once the Bootable USB drive is ready, you'll see Done on the screen. This process may take some time.
Installing macOS Mojave from the Bootable USB Drive
The final step is to perform a clean installation of macOS Mojave from the Bootable USB Drive.
Connect your Bootable USB drive to your Mac, then open or restart your Mac while simultaneously pressing and holding the Option key (Alt key on Windows) during startup. This action opens the Startup Manager window, where you can select to install macOS from the Bootable USB drive.
Select Disk Utility, then choose your hard drive and click Erase.
Return to the main window, select Install macOS.
After the installation process is complete, you can restore your apps and settings from a backup.
This guide from Mytour demonstrates the steps to cleanly install macOS. If you have any questions or need clarification, feel free to leave your comments below the article. Mytour will address your queries as soon as possible.
