Right click on the image file you just download using WinRar to extract the Image File on any. Running OS X El Capitan 10.11 in VirtualBox. I need to install OS X El Capitan 10.11 as guest OS in VirtualBox running on macOS High Sierra 10.13. I followed the instructions in this guide. I obtained the OS X El Capitan image from here and modified it as outlined in the guide. On startup I get a kernel/cpu panic and was unable to boot. In order to access Installation environment under VirtualBox, you will need to enter the VirtualBox EFI BIOS by pressing F12 few times, at very early stage of guest VM boot up. You will be greeted with an old school text mode BIOS interface, in which you should choose the Boot Manager option. Inside, launch EFI Internal Shell to enter EFI. The El Capitan Theatre is dedicated to offering you an outstanding Guest experience while including measures to keep you and our cast members safe and healthy. Click on Safety Information in the tab above for more information.
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.
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.
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.
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.
Can link with Cloud storage. 
Provides the facility to send documents to other. Handle your daily work, contacts, and notes effectively.
8. When you success install Mac In your VirtualBox, you can change default screen resolution using this command :
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 Baki sab first class hai moe song download.
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/
Mac Mini (late 2012) running El Cap (10.11.6) host with 16 GB RAM VirtualBox 5.2.8
Trying to install El Cap as guest using
Selecting In Wizard either Mac OS X (64 bit) or Mac OSX 10.11 El Capitan (64 bit) gives same end result
Assign 4 GB RAM
Create Virtual Hard disk - VDI Dynamically 49 GB
System settings ICH9 - enable I/O APC - enable EFI - Hardware Clock in UTC
Processor 1 CPU - Execution Cap 100% - enable PAE/NX
El Capitan Virtualbox Image
Paravirtualization interface is default - Hardware virtualization enable nested pagingDisplay 128 MB - 1 monitor - scale factor 100%
All other settings defaultStart VM and select 'Install OS X El Capitan.dmg' from the menu.
Booting starts. Pauses after ApplFSCompressionTypeZlib load succeeded.
Sometimes it stayes there forever (well longer than I can wait!) and sometimesz it goes on to
Missing Bluetooth Controller.
Another pause then screen turns to garbage with 'no enrtry' sign (circle with slash through it)