Step 2: Make a bootable flash installer of macOS You can make a backup of your Mac to iCloud drive or you have to make a Time Machine backup. Therefore, it is important for you to back up files, apps and other needed data on your Mac before the install of the new OS. To clean install a Mac OS, you have to first erase everything on the drive. We will cover the first one - how to clean install macOS High Sierra on Startup drive first. The methods to perform these two types of clean install are different. Fresh install on the non-startup, on the other hand, requires you to have a second drive on the Mac. To perform a clean install on the startup drive, you need to make a bootable USB install drive of macOS, such as macOS High Sierra. There are two types of clean install of macOS: installing Mac OS on the startup drive and installing the OS on non-startup drive. Part 2: Clean Install Mac OS from USB on Startup Drive Tip: If you need to recover deleted photos, files, videos, audio from Mac after clean installation, you can use FonePaw Data Recovery (opens new window). Comparing to upgrading to macOS High Sierra, a clean install is more likely to give your Mac a better performance and it is often used to fix Mac system problems, such as speeding up a slow Mac. By upgrading to macOS Sierra from Sierra, El Capitan, etc., current data on the Mac are preserved and you can use your apps, files, photos and other data right away once the upgrade is completed.Ĭlean install of Mac OS, on the other hand, will delete all current data on Mac's drive and install on the drive a with a fresh copy of macOS High Sierra. For example, as macOS High Sierra is released, we download the new operating system from App Store and run the installer to get it on our Mac.

Usually we install a new version of Mac OS by upgrading to the new version. Part 1: Clean Install Mac OS vs Upgrade Mac OS You can also apply these steps to clean install macOS Sierra, OS X El Capitan, or the older OS X version on your Mac. This tutorial will explain to you how to clean install macOS High Sierra step by step. A clean install of Mac OS will restore your Mac to factory settings and reinstall new Mac OS on the computer, which is right for you if you want to give your Mac/iMac/MacBook a fresh restart. Other than downloading and installing macOS from App Store, you can also upgrade your Mac to macOS High Sierra with a clean install.

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