Installing OS X El Capitan from a USB Drive Using an External Hard Disk or Flash Drive

If you're looking for alternative ways to install Mac Os 10.9 (El Capitan) without using the App Store, this article will walk you through the process of creating a bootable installation drive.

Step 1: Downloading OS X El Cap

To start, head over to Apple's official website and download the appropriate version of OS X El Capitan for your Mac. For most users running an Intel-based machine (which includes nearly all newer Macs), you'll want 'OS X El Capitan' rather than the older PPC or universal versions.

Step 2: Downloading the USB Creator App

Next, you will need to download and install a third-party app called 'USB Creator for OS X.' This free utility helps create bootable installation media from your downloaded .dmg file. You can find it here:

http://www.macworld.com/mac/applications/macosx-10-8-apps/1404osx-boot-drives.html

Step 3: Preparing the USB Drive or External Hard Disk

Before proceeding, make sure you have an external drive that is at least as large (or larger) than your Mac's hard disk. If using a flash drive, ensure it has enough free space available.

1. Plug in both devices.

2. Open 'Disk Utility' from Applications/Utilities (or directly via Spotlight).

3. Select the USB drive or External Hard Disk you want to use as your installation media.

4. Click Erase and choose 'Mac OS Extended (Journaled)' for the format type.

Step 5: Creating Your Bootable Installation Drive

1. Insert your Mac's recovery partition install disk into any available optical drive slot if necessary, then restart while holding down Command + Option keys until you see a spinning globe icon.

2. Select 'Boot from USB' or 'External Hard Disk' and press Enter when prompted to boot up using the newly created media.

Step 6: Finalizing Installation

Once your Mac boots off this external drive, follow these steps:

1. Double-clicking on 'Install OS X El Capitan' will launch a welcome screen.

2. Click Continue twice to proceed through several screens confirming your language preferences and keyboard layout settings.

3. Agree with the terms of service by checking both boxes at bottom left before clicking 'Continue.'

4. Select your desired installation destination (typically default: Macintosh HD).

5. Wait for the installer to copy necessary files over - this may take around 30 minutes depending on hardware speed.

After completing these steps, you should now have a fully functional OS X El Capitan installation ready-to-use without needing any internet connectivity!

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