How to Perform a Clean Install of macOS High Sierra

This is the easy way to perform a clean install of macOS High Sierra. We’ll show you how to make a bootable macOS High Sierra USB installer in just a few clicks, how to do a clean install of macOS High Sierra, and why you might want to do so instead of upgrading.

With this guide, you can do a clean install of macOS High Sierra on any Mac that supports it, even if you’re coming directly from OS X El Capitan rather than macOS Sierra.

Apple changed the macOS High Sierra disk format for devices, but you don’t have to worry about making that change when formatting your drive. The macOS High Sierra installer takes care of that for you.

Should I Clean Install or Update macOS High Sierra?

You don’t need to do a clean install of macOS High Sierra, but if you’re experiencing macOS Sierra issues and it’s been several years since you just installed macOS or OS X, you might want to take the challenge.

Besides getting rid of some issues, it helps you free up space by getting rid of things you never use, especially if you start completely from scratch instead of restoring a Time Machine backup.

A clean install erases everything on your Mac, while a basic install lets you upgrade directly over your files so you don’t have to worry about any additional installations.

What You Need for a macOS High Sierra Clean Install

You’ll need a large enough USB drive and you’ll need to download the macOS High Sierra installer from the App Store, even if you don’t use it for an upgrade. Collect the following items;

1. Download the macOS High Sierra installer from the App Store.
2. A 16GB Flash Drive that you can erase.
3. USB C Adapter if you have a MacBook
4. Time Machine Backup

This will erase the USB drive and you may need to reformat it later to get all the space back, but once that’s done, you’ll be good to go.

How to Make a Bootable USB macOS High Sierra Installer

Download the macOS High Sierra installer from the Mac App Store. This is a 5GB file and will take some time to complete. Once this is done, close the installer instead of running it. You can do this in the menu bar at the top of your screen.

1. Connect your USB drive to your Mac. You don’t need to format the drive specifically for this task, the app will take care of it all for you. This will delete the USB drive.
2. download Disc Creator and then click on Application.
3. Select the USB drive from the drop-down menu.
4. Click Select Installer if it’s not already selected and select the macOS High Sierra installer.
5. Click Create Installer.
6. Click Erase disk.
7. Wait for a confirmation that this is complete.

That’s all you need to do to make your own macOS High Sierra USB Installer. You can also use terminal and commands, but this is free and works great.

How to Do a Clean Install of macOS High Sierra

Start your clean install of macOS High Sierra.

You will need to insert your USB drive into the Mac where you want to use this USB macOS High Sierra installer. If you’re doing this on a newer mac, you may need a USB C adapter.

1. Shut down your Mac.
2. Restart your mac while holding down the option key.
3. Click Install macOS High Sierra.
4. Now click on Disk Utility.
   
5. Click on your Mac hard drive, then click Erase. For Format, choose mac OS Extended (Journaled). macOS High Sierra uses a new Apple File System, and the installer will make the change for you when you install it.
6. Name your hard drive Macintosh HD and then click delete.

Once that’s done, your Mac’s hard drive is wiped and ready to install macOS High Sierra. Click Install macOS and then continue with the installation. From here you can expect to spend 30 to 60 minutes to complete the setup.