Creating Mac OS El Capitan Boot Drives (10.11) for Clean Installs

With the introduction of a digital delivery systems for Apple software and operating systems a lot of people are finding themselves confused when comes how to do a clean install of the operating system on their machines. For clarification a clean install is when the hard drive of the machine is completely erased, formatted, and returned to a state where only the operating system is present.

Obtaining El Capitan

Getting Mavericks has never been easier. For starters its free so you have absolutely no reason to not be using the newest operating system from Apple. Simply launch the App Store from your system and search for El Capitan or just click here to download El Capitan from the App Store.

At 5.29gb downloading El Capitan may take a bit of time even on a high-speed internet connection so plan accordingly. Once the download is finished you will find a new application in your Applications folder called Install OS X El Capitan. You are going to want to copy this application onto a USB Key or External Drive. Once its copied over delete the copy from your Applications folder. Before you continue make sure your BACKUP anything you need from your system. There is no going back once you format the drive, so even if you think you have everything you need off the drive already double-check and make sure.

Creating a El Capitan Boot Installer

For this process you are going to need a USB Key that is at least 8GB in size. The next thing you’ll want to do is rename the USB Key that you wish to turn into a bootable installer drive. To avoid any confusion, we’re naming the USB drive to “ElCapitanInstall” (without the quotations), though you can name it whatever you want as long as you adjust the command line syntax to match. Note that when you are finished with the process the drive is going to end up being named “Install OS X El Capitan” so it really doesn’t matter what you call the drive.

Once you have your USB Drive ready to go launch the terminal application found on your computer at /Applications/Utilities/ You will need to enter the command found below exactly as it appears, if you named your drive something other than ElCpitanInstall you will need to adjust the command below.

sudo /Applications/Install OS X El --volume /Volumes/ElCapInstaller --applicationpath /Applications/Install OS X El --nointeraction

After entering the above command into the command line, you will be prompted to enter your password after enterprising your password it will erase the disk, and begin to copy the installer files over. Once the process is complete. It will display “DONE”. Until it says “DONE” its not finished. The process can take a little while so just let it do its things. Go have a cup of coffee or something. Once its complete you now have a bootable installer.

Formatting the Target Volume for Clean Install

  1. Boot your machine off of the USB Key We just made. Do this by holding down the option key while booting up the machine. You will now be able to select the drive you want to boot from. Boot from the USB Key we made.
  2. Instead of starting your installation select the utilities menu from the top of the screen and select disk utility, and select the drive you wish to do the install on.
  3. Now is a good time to stop and think about if you backed up everything you needed from the drive you are about to erase cause there is no going back.
  4. Select Erase, set the format to Mac OS Extended (Journaled) and enter the name of the Volume. The standard name for the primary volume is Macintosh HD but you can name it what ever you want.
  5. Now is a good time to stop and think about if you backed up everything you needed from the drive you are about to erase cause there is no going back.
  6. Once you are sure you have backed up everything you need, click erase.
  7. You will be presented with a prompt saying are you sure you want to do this all the data on the drive will be erased. Did you back everything up? If you are sure you are ready to continue click erase.
  8. You drive will now be erased, the process should only take a few seconds.
  9. Once the erase process is complete quite disk utility.

Installing El Capitan

  1. After quoting the disk utility application you should find yourself back at the standard installer screen.
  2. Click through the prompts until you are presented with the drive selection screen, select show all disks and select the newly erased volume from the previous steps. You will know you are selecting the correct volume because the disk color will be orange.
  3. Click Install and now wait. The first phase of the installation should take 3 – 10 minutes to complete at which point your machine will reboot.
  4. During this wait period you will suddenly find yourself wondering if you actually did backup everything you needed from the drive you just erased and in most cases the answer is actually no of course you didn’t. At least thats how it always turns out for me.
  5. Once your machine has restarted, the second phase of the installation will occur and this will take around 30 minutes to complete. You wont have to do anything during the process so feel free to go do something else, like write a blog post on how to do a clean install of El Capitan for example.
  6. Thats it your all done, other than of course going through the setup assistant process.

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