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.

In this article, I will show you how to install Mac OS X El Capitan on VMware on Windows PC.Therefore, Apple and Mac are trying to produce new versions of the Mac OS operating system, and Mac OS X El Capitan is one of the old version of the Mac OS operating system for Mac. Once you get the 'Install OS X El Capitan.app' from the Applications folder then you can use the install app to make a bootable USB installer or launch the 'Install OS X El Capitan.app' to do the install (Note: the 'Install OS X El Capitan.app' will automatically be deleted once it is run from the Applications folder, so it is a good idea to. FIX This Copy of the Install OS X El Capitan Application Can’t be Verified. If the issue is with your Computer or a Laptop you should try using Restoro which can scan the repositories and replace corrupt and missing files. This works in most cases, where the issue is originated due to a system corruption.

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

If you’ve never had El Capitan on this Mac, the first thing to do is visit the Mac App Store, download El Capitan (it’s free), and install it. 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.

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.

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:

El Capitan Reinstall

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

Install Os X 10.11

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.