Create Install Media El Capitan

I’m trying to sell a 2009 MacbookPro. It’s the model MacbookPro5.5 and Apple supports macOS El Capitan 10.11 as latest available version.

I’ve wiped all data from the installed SSD and had to boot from an external disk. Now I’ve got two problems:

  1. I’ve only got a Mac with Big Sur and Apple Silicon. I cannot use the package installer from the download provided by Apple to create the installer App for El Capitan. However, I need access to the installer so that I’m able to use the createinstallmedia command.
  2. The 2009 MacbookPro is already wiped and has only access to the recovery mode. You cannot execute the package installer in Recovery Mode to extract the media.

Enter the create partition primary command and press Enter to complete the process. Once you formatted the USB flash drive with a GPT partition, you can use the instructions mentioned above to use TransMac to create a bootable media, but this time skip steps No. 5 through 10 and continue on step 11. Once you’ve done that, here’s how to install, reinstall, or upgrade to El Capitan, step by step: Boot from your Recovery HD partition by restarting your Mac while holding down the Command+R keys. The OS X Utilities window appears. Select Reinstall OS X, and click Continue. The OS X El Capitan splash screen appears. Download: OS X El Capitan This will be downloaded as a disk image called InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, which has the name InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. Make El Capitan Bootable Usb On Windows. Just click on the setup file and with some click, the installation will finish. After that, Launch TransMac when TransMac is launched you will see the list of Flash drives or local disk. Then Right-click on that flash you want to create bootable USB for Mac OS El Capitan then select Restore with Disk Image. Restore with the Disk image. .media, HD floppies, dmg, dmg part, sparse bundle. Now it is the time to create a bootable USB installer using TransMac, To install Mac OS El Capitan on.

Luckily I’ve found this blog post from Chris Warrick who explained how to extract the installer App from the package:

  1. Attach an external Disk which contains the downloaded pkg from Apple. You’ll need enough space on that Disk to extract the pkg and it needs to be writeable
  2. Open the Terminal from inside the Recovery Mode
  3. Go to the mounted volume
  4. Extract the package:

Create Install Media El Capitan Free

Now we can try to create the install media from the installer app. Make sure you’ve attach another disk which can be overwritten by the installer. In this example its named “MyBlankUSBDrive”:

The InstallESD.dmg image is missing, which we’ll need to add to the right location:

Install el capitan on mac

Now we’ll have a valid installation medium which can be used to start the installer from. You can reboot from that disk and should be able to install El Capitan.

However, I’ve encountered another annoying issue which caused the installer to fail:

El Capitan Installer cannot be verified

Oh great… On to the next commands you can try from the Terminal inside the Recovery OS:

  1. installer -pkg /Volumes/Mac OS X Install DVD/Packages/OSInstall.mpkg -target /Volumes/'XXX' where XXX is the name of the disk you’re installing to.
  2. Wait for the installation to say it’s complete. You will not see any sort of progress display.

Great, you’ve got El Capitan installed! Apple had some issues with certificates and people found a way to either use the above commands for installation or you’ll have to tinker with your Macs time settings so that the signature is valid again. I would have expected that Apple resigned all installers so I wouldn’t have to use these commands at all but doesn’t look like they did.

Create Install Media El Capitan Installer

With a bootable Ubuntu USB stick, you can:

  • Install or upgrade Ubuntu, even on a Mac
  • Test out the Ubuntu desktop experience without touching your PC configuration
  • Boot into Ubuntu on a borrowed machine or from an internet cafe
  • Use tools installed by default on the USB stick to repair or fix a broken configuration

Creating a bootable USB stick is very simple, especially if you’re going to use the USB stick with a generic Windows or Linux PC. We’re going to cover the process in the next few steps.

Apple hardware considerations

Install El Capitan On Mac

There are a few additional considerations when booting the USB stick on Apple hardware. This is because Apple’s ‘Startup Manager’, summoned by holding the Option/alt (⌥) key when booting, won’t detect the USB stick without a specific partition table and layout. We’ll cover this in a later step.