How to Clean Install macOS

Edited 2 weeks ago by ExtremeHow Editorial Team

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If you're experiencing problems with your Mac or simply want to start fresh with your system, a clean install of macOS may be the solution you're looking for. A clean installation involves erasing your computer's hard drive and installing a fresh version of macOS. This process can resolve persistent issues by removing any corrupted files, applications, or system settings that may be causing problems.

Before you begin the clean install process, it's important to back up your data. A clean installation will erase all data on your Mac, so save anything important you might need later. You can use Time Machine, cloud storage, or an external hard drive to back up your files.

Preparing for a clean install

Before you begin the installation, make sure your Mac is compatible with the version of macOS you plan to install. Visit Apple's official website to check the system requirements for the latest version of macOS or the version you want to install. Make sure your Mac has enough storage space and meets other requirements such as RAM and processor compatibility.

Step 1: Back up your data

Backing up your data is the first and most important step. This ensures that you don't lose any important files during the clean install. Use Apple's built-in backup feature, Time Machine:

• Connect an external hard drive to your Mac.
• Open System Preferences and select Time Machine.
• Click Choose Backup Disk and select your external hard drive.
• Click Back Up Now to back up your data.

Step 2: Create a bootable installer for macOS

To clean install macOS, you'll need a bootable installer. Here's how to create it:

1. Download the macOS installer from the Mac App Store. The installer will be saved in the /Applications folder.
2. Insert a USB drive with at least 12 GB of available storage into your Mac.
3. Open the Terminal, which you can find in Applications > Utilities.
4. Use the following command to create a bootable installer, replacing Install macOS [Name] with the installer you downloaded and MyVolume with the name of the USB drive:

   sudo /Applications/Install\ macOS\ [Name].app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

5. Press Return and enter your administrator password when prompted.
6. Confirm that you want to erase the drive by typing Y and pressing Return.
7. When Terminal has downloaded and created the installer, it will notify you that the process is complete.

Clean installation process

Step 3: Erase your Mac's hard drive

Once the bootable installer is ready, you can begin the clean install. First, wipe your Mac's hard drive:

1. Connect your Mac to a power source and plug in the USB installer.
2. Restart your Mac and hold down the Option key until you see the Boot Manager screen.
3. Select the USB drive with the macOS installer and press Enter.
4. Once the macOS installer loads, select Disk Utility from the options.
5. In Disk Utility, select your startup disk—the drive where macOS is currently installed.
6. Click Erase at the top of the Disk Utility window.
7. Choose a format for the drive. If you're using macOS Big Sur or later, choose APFS. For earlier versions, you can choose Mac OS Extended (Journaled).
8. Enter a name for the disk and click Erase.
9. Once the disk is erased, exit Disk Utility to return to the macOS Utilities screen.

Step 4: Install macOS

Now that your hard drive is ready for a fresh start, it's time to install macOS:

1. From the macOS Utilities screen, select Install macOS.
2. Follow the onscreen instructions, and select your newly erased hard drive as the installation location.
3. The installer will begin copying the new system files to your drive. This process may take some time.
4. Once the installation is complete, your Mac will restart.

After a clean install

After the installation is complete and your Mac restarts, you'll be walked through the initial setup process. Here are a few things you'll need to do during setup:

• Select your country or region.
• Select your keyboard layout.
• Connect to a Wi-Fi network.
• Sign in with your Apple ID.
• Set up Siri and other features.

Once your initial setup is complete, you can begin restoring data from your backup. If you backed up your data using Time Machine, the system will offer the option to restore from a Time Machine backup during setup.

Troubleshooting tips

If you encounter any problems during the installation process, consider the following suggestions:

• Make sure your Mac is compatible with the version of macOS you're trying to install.
• Double-check that your USB installer is created correctly.
• Make sure you remain connected to a reliable power source during the entire process.

Final thoughts

Performing a clean installation of macOS can be a powerful way to resolve persistent software problems or give your Mac a fresh start. By carefully backing up your data and following the steps above to create a bootable installer and erase your hard drive, you can successfully clean install macOS and start fresh.

Remember to keep your software and backups updated regularly to maintain the health of your Mac. The clean install process, while resolving issues, also reminds any user about the importance of data management and system maintenance. Enjoy your fresh macOS system!

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