Once the installation is complete, the Mac will restart and display the factory fresh Welcome screen.

The system download is several Gigabytes in size, therefore the length of time is determined by the speed of your internet connection.

The computer will download a copy of macOS from Apple, and install it on the disk.

There will only be one option in most cases.

When prompted to select an install disk, select the disk that we had just erased.

Follow the install prompts in the installation guide, read and agree the terms and conditions.

Now that you are connected to the Internet, click Reinstall macOS in the macOS Utilities menu.

Connect to a Wi-Fi network by clicking on the Wi-Fi icon at the top right of the menu bar. An Internet connection is required to download a copy of macOS from Apple.

After erasing the disk you are ready to move on to the operating system installation.

MacintoshHD is the default disk name in macOS, disk format required is Mac OS Extended (Journaled), and the Scheme is GUID Partition Map.

Click on the Erase button at the top of the Disk Utility, this brings up our disk formatting options.

It will be called Apple SSD on recent Macs. Select the Internal storage disk in the left-hand menu.

Open Disk Utility to begin the disk erasing process.

The macOS Utilities menu will appear after a few minutes.

The computer will begin to boot into the MacOS Recovery mode.

Restart your Mac and hold down the following button combination:.

We are assuming you already copied all your data to an external backup, or to your new Mac, because the following steps will really erase your disk. We are erasing a 2014 MacBook Air running MacOS 10.12 Sierra, but the steps will be similar with any recent Mac. Steps may vary with different version of macOS, and hardware configurations but the general idea is the same. Budget at least an hour for this process, slower Internet connections and older hardware will take longer.

A Wi-Fi network with an active Internet connection.

Erasing your storage drive and performing a fresh install using macOS Recovery This is much quicker than rewriting that disk space with blank data, and it also gives you a chance to recover accidentally deleted files with handy recovery software. We recommend erasing the drive with Apple’s Disk Utility keep your personal data safe. Instead, the reference to the file is removed from the file system (which keeps a list of all the files on your computer), so the computer is able to write new information in the same physical area when space is needed.

When you empty your trash bin on your Mac, the files are not really erased. Why you need to erase your hard drive/SSD

Erasing disk utility mac