I have 2 Macs, and am downloading El Capitan from the app store. I want to see if I can install it on an older MacBook Pro that has a broken Command-R feature that prevents me from installing the OS. (It says contact apple support) Since that costs $, I'd rather see if I can simply boot and reinstall the OS in a clean way. Sep 30, 2015 The new OS X El Capitan features a new Split View, features in Safari, Mail, Notes, Maps, and Photos, and more. To get your hands on all this new stuff, you have to install the operating system on. I created a USB disk with a bootable El Capitan as per this documentation. Plug-in your USB key on a turned-off computer. Start your Mac, press immediately OPTION (aka ALT) Select the Orange icon (aka a USB stick) labelled El Capitan. If it does not detect it after 10 sec and you only see your hard-drive. Try another USB port and wait 10 sec again.

• Apple El Capitan Install Disk
• Install Sierra
• Apple Install El Capitan
• Apple Install El Capitan From Usb
• Apple Install El Capitan From An External Volume

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:

Apple El Capitan Install Disk

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.

Install Sierra

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:

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:

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

Apple Install El Capitan

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

Apple Install El Capitan From Usb

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.

Apple Install El Capitan From An External Volume

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.