This is the easy way to perform a macOS High Sierra clean install. We’ll show you how you can make a bootable macOS High Sierra USB installer with just a few clicks, how to do a clean macOS High Sierra installation and why you may want to do it 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 are coming from OS X El Capitan instead of directly from macOS Sierra.
Apple changed the disk format for macOS High Sierra for devices but you don’t need to worry about making that change when you format your drive. The macOS High Sierra installer handles that for you.
Should I Do a Clean Install of macOS High Sierra or Update?
You don’t need to do a macOS High Sierra clean install, but if you are suffering with macOS Sierra problems and it’s been several years since you installed macOS or OS X fresh, you may want to go through this hassle.
In addition to getting rid of some problems, it will help free up space by getting rid of things you never use, especially if you start over completely from scratch instead of simply restoring a Time Machine backup.
A clean install erases everything on your Mac while the basic installation allows you to upgrade right over your files so that you don’t need to worry about any additional setup.
What You Need for a macOS High Sierra Clean Install
You will need a large enough USB drive and you still need to download the macOS High Sierra installer from the App Store, even though you’re not using it to upgrade. Gather the following items;
- Download the macOS High Sierra installer from the App Store.
- A 16GB Flash Drive that you can erase.
- USB C Adapter if you have a MacBook
- Time Machine Backup
This will erase the USB drive and you may need to reformat it to get all the space back later, but once this is complete you will be ready 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.
- Connect your USB drive to your Mac. You don’t need to format the drive specially for this task, the app will handle all of that for you. This will erase the USB drive.
- Download Disk Creator and then Click on the App.
- Choose the USB drive from the drop down.
- If not selected click on Choose Installer and pick the macOS High Sierra installer.
- Click Create Installer.
- Click Erase disk.
- 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 it works great.
How to Do a Clean macOS High Sierra Install
You’ll need to plug your USB drive into the Mac that you want to use this USB macOS High Sierra installer on. You may need a USB C adapter if you are doing this on a newer mac.
- Turn your Mac off.
- Reboot your mac while holding the option key.
- Click on the Install macOS High Sierra option.
- Now click on Disk Utility.
- Click on your mac hard drive and then on Erase. Choose mac OS Extended (Journaled) for the format. macOS High Sierra uses a new Apple File System and the installer will make the change for you when you install.
- Name your hard drive Macintosh HD then click erase.
Once this completes, your Mac’s hard drive is erased and ready for the macOS High Sierra installation. Click on install macOS and then proceed with the installation. From here on out you can expect to spend 30 to 60 minutes to complete the installation.