How to reinstall macOS: step by step instructions

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Choose one of three methods and your Mac will be as good as new in less than an hour.

1. Connect your Mac to a power source

This item only applies to laptops. If you have a stationary Mac, go to the next step.

The installation process takes a certain amount of time, while actively using the processor and disk, so that the MacBook can be discharged at the most inopportune moment. To avoid trouble, be sure to connect your device to the power adapter. Even if the battery is 100% charged.

2. Save important data

With a clean install of macOS, the disk is formatted and absolutely all information on it is deleted. Therefore, you first need to make a backup using Time Machine or save the necessary data manually.

3. Select the installation method

You can use an external drive, a recovery partition on a disk, or a remote Apple server as a distribution source for installing macOS. Which option to choose depends on the situation and your preferences.

Installing macOS from a boot disk

The most reliable and fastest way. You can install any version of macOS that your particular Mac is compatible with. You will need a USB stick of at least 8 GB, which you will need to prepare in advance.

Reinstall macOS from the recovery partition

A convenient alternative to a USB flash drive. The source of the distribution is the recovery partition that was created during the previous installation. Accordingly, after reinstallation, there will be the version of macOS that is currently used on the Mac.

Recover macOS over the Internet

An option for situations when there are some problems with the disk or there is no flash drive at hand. The installer is preloaded over the web, so you have to wait. You can install either the most current compatible macOS, or the original version that was on your Mac when you bought it.

4. Start recovery mode

If your computer has a firmware password, you will need to enter it to boot into recovery mode.

Depending on the selected OS installation method, the transition to the recovery menu differs slightly. Proceed as follows.

Installing macOS from a boot disk

Create a bootable USB stick and connect to one of the USB ports. Turn on or restart your Mac while holding down the Option key until the computer starts up. Select your USB flash drive from the boot menu.

Reinstall macOS from the recovery partition

Turn on or restart your Mac, and then press and hold the Cmd + R keys until the computer boots up.

MacOS Online Recovery

Turn on or restart your computer, and then immediately press and hold one of the keyboard shortcuts until your Mac starts up:

• Option + Cmd + R - to install the latest version of macOS.
• Shift + Option + Cmd + R - to install the original OS at the time of the Mac purchase.

5. Format the disk

Erasing a disk is the same, regardless of the reinstallation method. Open Disk Utility from the macOS Utilities menu and select the system drive from the left pane. It is usually called Macintosh HD and is located in the Internal section.

Click the Erase button and then specify the file system format. Choose macOS Extended (Journaled) for High Sierra and other earlier versions, APFS for macOS Mojave and newer.

Give the disk any name, you can leave the standard Macintosh HD. Confirm erasing and wait for the process to finish. Close Disk Utility and return to the main recovery screen.

6. Install the operating system

Like formatting, the process for installing an operating system is the same for any of the options. From the macOS Utilities menu, click Reinstall macOS and select the drive you are using on the partition selection screen. Follow the prompts of the installation wizard.