This post is actually part of a more specific article I wrote that explains how to install OSX on a Virtual Machine in VirtualBox. You can find this other article here:
Install OS X on VirtualBox (on OS X)

This guide will show how to create an installer of your OSX system. Once done, you will be able to use it if you want for example wipe your current system and start fresh with a brand new OSX Installation, or proceed and use it to install it on a VM as I mentioned before.

I will show how to download the latest version of OSX (El Capitan at the time of this article) or an older one you previously owned (Yosemite for example).

Download the latest OS X Version (El Capitan)

To download it, you can pass through a web browser going there:
https://itunes.apple.com/gb/app/os-x-el-capitan/id1018109117

and clicking then “View in Mac App Store”:

To select then “Launch Application” and land in the App page on the App Store:

Or open directly the App Store on your mac:

and search for “El Capitan”:

Despite how you reach this stage, you will have then click on the App or just select “download” and…

… wait and wait…

Once the download is complete you can see the installer in the Application folder:

Prepare the USB

In order to create the installer you need to insert a USB stick (I will use a 16GB drive).

It is not strictly required to wipe the whole content of the USB drive but it is something I prefer to do anyway… and it takes really few seconds to do so (feel free to skip this section if you really want to).

Open “Disk Utility“.

You can find this app in the Applications/Utilities folder:

Or use Spotlight search (that you can open with CMD⌘ + SPACE) and start typing “Disk Utility”:

Once started, locate your drive on the left side (it should be easy to identify in the “External” section).

Select it and click the “Erase”:

At this point give the drive a label (it will not really matter if you are going to create an installer because it will be automatically changed later on), select the Format “OS X Extended (Journaled)” and “GUID Partition Map” for the Scheme:

Click “Erase” and wait for the operation to complete. Then click “Done”:

Time to create the installer.

Create a Bootable USB Installer

We need now to put the installer on this USB drive and make it bootable.

Open the Terminal window.

You can find it again in the Applications/Utilities folder or as usual with Spotlight (CMD⌘ + SPACE) search for “Terminal”:

NOTE: Assuming you named the USB drive “OSX”, the volume will be in “/Volume/OSX“. If you gave it a different name you will need to change the following command in order to point it to the correct location of your volume.

Type the following command:

Type your password (you will require root privileges), type “Y” when required to confirm your action and wait for the configuration to complete… it could take some time, so be patient (I’m talking even over 30 mins!):

Note that this procedure will erase the content of the USB and change its label to “Install OS X El Capitan“.

DONE!

Install OSX!

Doing so you should see a startup selection screen similar to this one:

where you can select your newly created installer USB and follow the installation procedure.

Enjoy :)

Download a previous OS X Version (Yosemite)

If you want to download a previous version of OS X you will soon notice that it will not be available on the App Store for download.

There is still a way though if you already purchased it in the past.

To access it open the App Store, and click the “Purchased” section:

Scan through your list and locate Yosemite:

Click the “Download” button and confirm your intention to Apple clicking “Continue” on the popup:

Wait then for the download to complete:

At the end of the download:

you could receive another message from Apple that just says that this is an old version of the OS. Just ignore it:

The installer will be placed in the “Applications” folder:

You can now proceed with the same procedure described above for El Capitan if you want to create a USB Installer.

That’s all!

If you enjoyed this article, found it interesting or just learned something new (or simply liked it) please share it, comment or feel free to if you think I deserved it or you simply want to show your appreciation :). In any case thanks for passing by and until next time!