I am very interesting to install Mac OS in my desktop computer using VirtualBox. I have created steps how to install Mac OS in VirtualBox. But, you need existing Mac OS to create bootable Mac OS.

Start with going to AppStore and installing El Capitan, so you'll have an application named Install El Capitan in your Application list. Then, you should follow the steps below. There is an installation image file inside /Applications/Install El Capitan.app, named InstallESD.dmg. It's not a bootable ISO that can be used to install the system on. Open virtualbox and click ‘New’ to create a new virtual machine with the following details: Name: El Capitan Type: Mac OS X Version: Mac OS X 10.11 El Capitan (64 bit) Click next, select 4GB of RAM, and next again. Select the El Capitan image that you have downloaded and unzipped as the disk image, and create the machine.

I want to install Mac El Capitan (10.11) in my VirtualBox. I dont have fast internet connection. So, I am search an iso Mac El Capitan over internet.

Mac Os High Sierra Iso For Virtualbox

1. Download El Capitan iso image. If you have bootable Mac, you can continue to step 4. I donwnload the iso image from this link : http://getpcsoft.wikisend.com/mac-os-x-1011-el-capitan-free-download.html.

OS: Mac OS X El Capitan (64 bit) RAM: As much as possible Hard disk: VDI, Dynamically Allocated, 500 GB or more, Close Virtualbox and open a Command Prompt with Admin privileges. Then, type the following (Replace the parts in capitals. Quotes are necessary).

2. The Mac iso image from link above not bootable (El Capitan.dmg). So, we need to convert Mac not bootable to iso bootable. I have convert *.dmg file to iso bootable iso using this script (you need to run this script from your existing Mac).

3. Using above script, we get ElCaption.iso. This file is bootable iso image needed to install El Capiton (Mac 10.11) in VirtualBox.

4. Open VirtualBox, create a new Mac project. I have created project using this setting. If you want change project Name, dont forget to edit text command in next steps too.

5. Close VirtualBox. Choose a Mac Model similar to your host system. Open your console and type this text. I have choose “MacBookPro11,3” in my desktop computer.

6. Optional- For some host systems eg those with Haswell CPUs, you might have to spoof an older CPU to avoid VirtualBox errors. You can try from one of the following if this happens:

7. Open VirtualBox and run our Mac10.11 Project. I think you already know how to install Mac in your computer. If not, you can search over internet.

8. When you success install Mac In your VirtualBox, you can change default screen resolution using this command :

El Capitan Os X Download

9. Adding serials and other SMBIOS details for the System Information Screen (optional)

I have success using this steps and this is how look Mac 10.11 in VirtualBox

Mac Os Iso File For Virtualbox

Source :
http://forums.macrumors.com/threads/how-to-create-el-capitan-os-x-bootable-dvd.1923894/page-2#post-22048507
http://anadoxin.org/blog/creating-a-bootable-el-capitan-iso-image.html
http://www.insanelymac.com/forum/topic/309654-run-vanilla-os-x-el-capitan-yosemite-or-mavericks-in-virtualbox-5010-on-a-windows-host/