Mac_OS_X_10.11.6_El_Capitan.part09.rar
The other installation process is known as the clean install. It replaces the contents of a selected volume with a new, pristine version of OS X El Capitan that does not include any previous versions of the operating system, applications, or data files that may have been present on the selected drive. The clean install method is a good choice for testing a new OS on a dedicated drive or partition, or when you have been experiencing software related issues with your Mac that you have not been able to fix. When the problems are severe enough you may be willing to trade keeping all of your apps and data for starting with a clean slate.
It's the second option, a clean install of OS X El Capitan, which we'll address in this guide.
What You Need Before Installing OS X El Capitan
Before proceeding, you should first verify that your Mac is capable of running OS X El Capitan; you can do this by visiting:
OS X El Capitan Minimum Requirements
Once you've checked out the requirements, come back here for the next, extremely essential, step:
Back Up Your Existing Version of OS X and Your User Data
If you're going to install OS X El Capitan on your current startup drive using the clean install method, then you will by definition erase everything on the startup drive as part of the process. That’s everything: OS X, your user data, anything and everything you have on the startup drive will be gone.
No matter why you're undertaking a clean install, you should have a current backup of the existing startup drive's contents. You can use Time Machine to perform this backup, or one of the many cloning apps, such as Carbon Copy Cloner, SuperDuper, or Mac Backup Guru; you can even use Disk Utility. The choice is up to you, but whatever you choose, it's important to take the time to create a current backup before you start the installation.
Types of Clean Installs
There are actually two types of clean installs you can perform.
Clean Install on Empty Volume: The first option is the easiest: installing OS X El Capitan onto an empty volume, or at least one whose contents you don’t mind removing. The key point is that you're not targeting your current startup volume as the destination for the clean install.
This type of clean installation is easy because, since the startup drive isn't involved, you can perform the clean install while booted from the current startup drive. No special, custom-made startup environment needed; just start up the installer and go.
Clean Install on Startup Volume: The second option, and perhaps the more common of the two, is to perform a clean install on the current startup drive. Because the clean install process erases the contents of the destination drive, it's obvious that you can't boot from the startup drive and then try to erase it. The result, if it were possible, would be a crashed Mac.
That’s why if you choose to clean install OS X El Capitan on your startup drive, there's an extra set of steps involved: creating a bootable USB flash drive that contains the OS X El Capitan installer, erasing the startup drive, and then starting the clean install process.
Check the Target Drive for Errors
Before you start any installation process, it is a good idea to check the target drive for problems. Disk Utility can verify a disk, as well as perform minor repairs if a problem is found. Using Disk Utilities First Aid feature is a good idea before you start the install process.
Repair Your Mac's Drives With Disk Utility's First Aid
Perform the steps outlined above, when completed return here to begin the installation process.
Let's Get Started
If you haven't yet downloaded a copy of OS X El Capitan from the Mac App Store, you'll find instructions for how to do this on Page 2 of the How to Upgrade Install OS X El Capitan on Your Mac. Once the download completes, come on back here to continue the clean install process.