Below are the steps needed to create an USB flash drive El Capitan bootable installer. Download the InstallMacOSX.dmg file by clicking on the OS X El Capitan 10.11 link in the Apple document 'How to get old versions of macOS'. These instructions assume this file has been downloaded to your /Downloads folder. The bootable El Capitan installer has been created on the flash drive. You can use this bootable installer to perform any of the supported installation types, including an upgrade install or a clean install. You can also use it as a bootable troubleshooting tool that includes an assortment of apps, including Disk Utility and Terminal.

Are you trying to make a bootable installer? Do you have the El Capitan installer downloaded from the App Store? You cannot make a bootable DVD but you can make a bootable flash drive.

Bootable USB Installers for OS X Mavericks, Yosemite, El Capitan, and Sierra

First, review this introductory article: Create a bootable installer for macOS. Second, see this How To outline for creating a bootable El Capitan installer. Simply replace the Terminal command with the one from the preceding article by copying it into the Terminal window. You will need an 8GB or larger USB flash drive that has been partitioned and formatted for use with OS X.

Drive Partition and Format

Open Disk Utility in the Utilities' folder.
After Disk Utility loads select the drive (out-dented entry with the mfg.'s ID and size) from the side list.
Click on the Erase tab in the Disk Utility toolbar. Name the drive, 'MyVolume'. <---- IMPORTANT!
In the drop down panel set the partition scheme to GUID. Set the Format type to Mac OS Extended (Journaled.)
Click on the Apply button and wait for the Done button to activate. When it does click on it.
Quit Disk Utility.

Create Installer

Make bootable el capitan installer on windows

Open the Terminal in the Utilities' folder. Choose the appropriate command line (in red) depending upon what OS X installer you want. Paste that entire command line from below at the Terminal's prompt:

Command for macOS High Sierra:

sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install macOS High Sierra.app

Command for macOS Sierra:

sudo /Applications/Install macOS Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install macOS Sierra.app

Command for El Capitan:

sudo /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install OS X El Capitan.app

Command for Yosemite:

sudo /Applications/Install OS X Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install OS X Yosemite.app

Command for Mavericks:

sudo /Applications/Install OS X Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install OS X Mavericks.app

El Capitan Bootable Usb Installer

Press RETURN. You will be asked for your admin password. It will not echo to the Terminal window. Then press RETURN again. Wait for the return of the Terminal prompt signifying the process has completed. It takes quite some time to finish. Be patient.

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El Capitan Bootable Installer