Install Disk Creator
Simplify creating a bootable macOS installer
What’s needed for a clean install on a Mac
- A backup of the disk before it’s erased. Two options are to use Duplicate (a free utility which can copy and paste an entire bootable volume), or Mac Backup Guru (a fully featured backup utility with unique incremental backups capability) for that.
Here is a detailed guide for the clean install process.
A Mac operating system installer. MacOS Sierra can be downloaded by clicking here.