How to reinstall macOS

Complete guide with multiple methods and troubleshooting.

7-10 min read
Expert Verified
Last Updated: August 2025

Quick Answer

Reinstalling macOS can restore your system to its original state, fix persistent issues, or prepare your Mac for a new user. This process can be accomplished through various methods, including Internet Recovery, macOS Recovery, or creating a bootable USB installer.

Beginner/Intermediate⏱ 7-10 min read

Prerequisites & Requirements

Before starting the reinstallation process, ensure you meet the following requirements:
  • •Compatible Mac model (check Apple's support page for compatible models with the desired macOS version).
  • •At least 15-20 GB of free disk space for the installation process.
  • •A stable internet connection if using Internet Recovery.
  • •Admin privileges on the Mac to perform the installation.
  • •Backup important data using Time Machine or another backup solution to prevent data loss.

Method 1: Reinstall macOS via Recovery Mode

This method is suitable for most users and can be used to reinstall macOS without losing data. It is recommended when facing system issues or preparing for a new user.
  • •Step 1: Restart your Mac. As it boots up, hold down Command (⌘) + R until you see the Apple logo or a spinning globe.
  • •Step 2: Once in Recovery Mode, select 'Reinstall macOS' from the macOS Utilities window and click 'Continue'.
  • •Step 3: Follow the on-screen instructions. You will need to agree to the software license agreement and select the disk where macOS is installed (usually named 'Macintosh HD').
  • •Step 4: Wait for the installation to complete. Your Mac will restart automatically. Verify successful installation by checking the macOS version in 'About This Mac' from the Apple menu.
  • •Step 5: If the installation fails, check your internet connection or try again after restarting your Mac.

For macOS Monterey and later

If you are using macOS Monterey or later, the Recovery Mode interface may have slight visual differences but the steps remain the same.
  • •Look for the new interface design in the macOS Utilities window, which may include updated icons.
  • •Ensure you have a reliable internet connection as the installation files may need to be downloaded.

For macOS Big Sur and earlier

For users on macOS Big Sur or earlier, the steps are similar but may have older interface elements.
  • •The Recovery Mode may display a more classic interface with different icons.
  • •Ensure your Mac is connected to a power source during the installation process.

Method 2: Creating a Bootable USB Installer

This method is useful for reinstalling macOS on multiple Macs or when Recovery Mode is not accessible. It requires a USB drive with at least 16 GB of space.
  • •Step 1: Download the macOS installer from the App Store (e.g., macOS Ventura).
  • •Step 2: Insert a USB drive and open 'Disk Utility' (Applications > Utilities > Disk Utility). Select the USB drive and format it as 'Mac OS Extended (Journaled)' with the GUID Partition Map scheme.
  • •Step 3: Open Terminal (Applications > Utilities > Terminal) and run the following command, replacing 'MyVolume' with the name of your USB drive: sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
  • •Step 4: Press Enter and provide your admin password when prompted. Wait for the process to complete.
  • •Step 5: Restart your Mac while holding the Option (⌥) key. Select the USB drive from the boot menu and follow the on-screen instructions to reinstall macOS.

Troubleshooting Common Issues

If you encounter issues during the reinstallation process, consider the following solutions:
  • •Error: 'An error occurred while preparing the installation' - Solution: Ensure your Mac is connected to the internet and try again. If the issue persists, restart your Mac and try Recovery Mode again.
  • •Issue: 'The installation failed' - Fix: Check that your disk has enough free space and is not corrupted. Use Disk Utility to verify and repair the disk.
  • •Problem: 'Cannot connect to the Apple ID server' - Workaround: Check your internet connection and try again later. Ensure that your router is functioning properly.

Advanced Tips & Shortcuts

For power users, here are some tips to streamline the reinstallation process:
  • •Keyboard shortcut: Command (⌘) + Option (⌥) + R - This combination will start your Mac in Internet Recovery mode, allowing you to reinstall the latest compatible macOS version.
  • •Command line: 'diskutil list' - This command in Terminal will show all connected disks and partitions, helping you identify the correct disk to install macOS.
  • •Hidden feature: 'macOS Terminal' - Access advanced installation options by using Terminal commands during Recovery Mode.

Common Mistakes to Avoid

Avoid these common pitfalls:

Expert Tips

The best approach to reinstall macOS is to use Recovery Mode, as it is straightforward and preserves user data. Always ensure your data is backed up before proceeding.