These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.

What you need to create a bootable installer

A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Download macOS

Mac OS X El Capitan 10.11.1 InstallESD DMG free download standalone offline setup for Windows 32-bit and 64-bit. The macOS X El Capitan 10.11.1 is a powerful application providing stability, compatibility and the security of the Mac along with different updates and enhancements. Apr 27, 2021 Download: OS X El Capitan This downloads as a disk image named InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder.

Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra
These download to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing installation. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server.
Download: OS X El Capitan
This downloads as a disk image named InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Terminal

Connect the USB flash drive or other volume that you're using for the bootable installer.
Open Terminal, which is in the Utilities folder of your Applications folder.
Type or paste one of the following commands in Terminal. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace MyVolume in these commands with the name of your volume.

Install El Capitan. OK, now you can click that Continue button in the installer window. (If the installer isn’t running, go to your Applications folder and double click the Install OS X El.
7 Download OS X EL Capitan. OS X El Capitan (version 10.11) is the twelfth major release of OS X (now named macOS), Apple Inc.’s desktop and server operating system for Macintosh computers. It is the successor to OS X Yosemite and focuses mainly on performance, stability, and security. Following the Northern California landmark-based naming.

Big Sur:*

Catalina:*

Mojave:*

High Sierra:*

El Capitan:

* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument and installer path, similar to the way this is done in the command for El Capitan.

After typing the command:

Press Return to enter the command.
When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
After the volume is erased, you may see an alert that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.

Use the bootable installer

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes.
Select the volume containing the bootable installer, then click Continue.
When the macOS installer opens, follow the onscreen instructions.

Intel processor

Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
Release the Option key when you see a dark screen showing your bootable volumes.
Select the volume containing the bootable installer. Then click the up arrow or press Return.
If you can't start up from the bootable installer, make sure that the External Boot setting in Startup Security Utility is set to allow booting from external media.
Choose your language, if prompted.
Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.

For information about the createinstallmedia command and the arguments you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:

Mac operating system’s twelfth major version is the El Capitan Installer (version 10.11). All the Mac computers which don’t have the privilege to upgrade to MacOS High Sierra or the computers that need to upgrade to El Capitan first, can download this twelfth version on the computer. This is the very last version of the Mac operating system which comes under the name OS X. And it is named as ‘El Capitan’ after the formation of a rock in the Yosemite National Park. El Capitan Installer is the post version to the Yosemite, and it was built by adding up more improvements to the Yosemite. In this version of the Mac operating system, the Apple Inc. has focused on the performance, stability, and security of the computer. Anyone who is interested can download it on the Mac PC.

How to download El Capitan Installer?

If you want to upgrade to OS X El Capitan, first you have to collect gather your Mac PC and then download the El Capitan Installer. That’s what we are going to do now.

Go to the App Store and open the El Capitan page there.
Then you must click on the ‘Download; button on the El Capitan Page.
If your Mac PC is compatible to perform this upgrade, a file named ‘Install OS X El Capitan’ will download to your Applications folder.
The installer will open automatically after finishing the download process. All you have to do next is click on the ‘Continue’ button and follow the onscreen instructions.

Upgrade Mac OS Version with El Capitan Installer while Protecting your Data

Before executing the Upgrade, you must prepare the Mac PC for the El Capitan Update. For that, gather these requirements first.

The Mac PC must have at least 2GB of memory and 8.8GB of storage space.
The PC must have at least 45% of battery life.
Connect the Mac PC to Wi-Fi or any other internet connection.
The Mac Apps must be up to date with the latest versions.
Take backups of all your personal data and present OS of the Mac PC.

Important! It is very important to backup your important data on the Mac PC to an external storage device because it will help you to avoid the data loss issues. If any case, you forgot to backup the data, your data may be lost while executing the El Capitan Installer update. So make sure you make a backup of the device data.

How to use El Capitan Installer for a Clean Install?

01. El Capitan Clean Install on Empty Volume with El Capitan Installer

This is the easiest method for the clean install. Here, you can install the OS X El Capitan Installer onto an empty volume, or you can use a s

Download Mac Os X El Capitan Installer