What to Know

• Insert USB installer, restart Mac and hold the Option key, open Disk Utility, erase the startup drive, and install Mavericks on this drive.
• Before you begin, back up your Mac and create a bootable version of the OS X Mavericks installer on a USB drive.
  

 A clean install of OS X Mavericks allows you to start fresh, either by erasing all of the data on your startup drive and then installing OS X Mavericks or by installing Mavericks on a non-startup drive; that is, a drive that doesn't contain an operating system. Here's how to perform a clean install of OS X Mavericks; all you need is a USB flash drive.