How do install OS X El Capitan onto a VM

Solution 1:

Preface:

This how-to targets VirtualBox because the OP uses it. I strongly recommend to purchase Parallels Desktop or VMware Fusion though. A lot of features like drag-and-drop, change the monitor resolution etc. don't work properly in VirtualBox (or I don't get it to work).

The installation of El Capitan is a dual-stage process. You first have to create a Yosemite VM and then update to El Capitan.

The script below apparently doesn't work with El Capitan. A "bootable" El Capitan iso boots to an EFI command line only. The intermediate step of creating a Yosemite.iso seems to be inevitable.

• Download the latest VirtualBox installer, the latest Yosemite installer and the latest El Capitan installer.

• Install VirtualBox

• Use the following shell script to create a bootable Yosemite.iso. The script assumes that Install OS X Yosemite.app was downloaded to the folder /Applications.

   #!/bin/bash  
  
   # Create bootable Yosemite ISO
  
   # Mount the installer image  
   hdiutil attach /Applications/Install\ OS\ X\ Yosemite.app/Contents/SharedSupport/InstallESD.dmg -noverify -nobrowse -mountpoint /Volumes/install_app
  
   # Convert the boot image to a sparse bundle  
   hdiutil convert /Volumes/install_app/BaseSystem.dmg -format UDSP -o /tmp/Yosemite
  
   # Increase the sparse bundle capacity to accommodate the packages  
   hdiutil resize -size 8g /tmp/Yosemite.sparseimage
  
   # Mount the sparse bundle for package addition  
   hdiutil attach /tmp/Yosemite.sparseimage -noverify -nobrowse -mountpoint /Volumes/install_build
  
   # Remove Package link and replace with actual files  
   rm /Volumes/install_build/System/Installation/Packages
   cp -rp /Volumes/install_app/Packages /Volumes/install_build/System/Installation/
  
   # Copy Base System  
   cp -rp /Volumes/install_app/BaseSystem.dmg /Volumes/install_build/
   cp -rp /Volumes/install_app/BaseSystem.chunklist /Volumes/install_build/
  
   # Unmount the installer image  
   hdiutil detach /Volumes/install_app
  
   # Unmount the sparse bundle  
   hdiutil detach /Volumes/install_build
  
   # Resize the partition in the sparse bundle to remove any free space  
   hdiutil resize -size `hdiutil resize -limits /tmp/Yosemite.sparseimage | tail -n 1 | awk '{ print $1 }'`b /tmp/Yosemite.sparseimage
  
   # Convert the sparse bundle to ISO/CD master  
   hdiutil convert /tmp/Yosemite.sparseimage -format UDTO -o /tmp/Yosemite
  
   # Remove the sparse bundle  
   rm /tmp/Yosemite.sparseimage
  
   # Rename the ISO and move it to the desktop  
   mv /tmp/Yosemite.cdr ~/Desktop/Yosemite.iso
  

  Copy the above lines, paste it into a new document prepare_yosemite_iso.sh on your desktop with a decent editor (below I use nano) and make it executable. In Terminal enter:

  touch ~/Desktop/prepare_yosemite_iso.sh
  nano ~/Desktop/prepare_yosemite_iso.sh #paste the content of the script here, save the file to disk with ctrl-O and quit nano with ctrl-X
  chmod +x ~/Desktop/prepare_yosemite_iso.sh
  

• execute the script:

  ~/Desktop/prepare_yosemite_iso.sh
  

  After several minutes the iso with the name Yosemite.iso will be moved to your desktop.

• Start VirtualBox and create a new Yosemite VM with the default settings.

• If your Mac contains a Haswell processor you have to change the the cpuid in the VM. Enter the following in Terminal:

  VBoxManage list vms #to list all available VMs
  VBoxManage modifyvm <name_of_vm> --cpuidset 00000001 000306a9 00020800 80000201 178bfbff
  

• Attach Yosemite.iso to the optical drive

• Boot the VM, format the hdd, then install and configure Yosemite.
• Copy the downloaded Install OS X El Capitan.app to the Applications folder in the VM. Use a network share on the host to accomplish that.
• Start Install OS X El Capitan.app and update the VM to El Capitan.

• To enable some screen resolutions shut down the VM and enter in (the host's) Terminal:

  VBoxManage setextradata <name_of_vm> VBoxInternal2/EfiGopMode N
  

  where N can be one of 0,1,2,3,4,5 referring to the 640x480, 800x600, 1024x768, 1280x1024, 1440x900, 1920x1200 screen resolution respectively

• Do Ruby development...