If you are trying to make a bootable installer or get El Capitan running on a virtual machine, 🛠️ Getting the Official Image
This is the most common error when working with older Mac ISOs. It happens because the original security certificates wrapped inside the installer have expired.
First, create a temporary blank disk image on your desktop where the installation files will be assembled. macosxelcapitan10111imageiso work
mv ~/Desktop/ElCapitan10.11.1.cdr ~/Desktop/ElCapitan10.11.1.iso
Building your own ISO ensures that the installer has not been modified. You will need a Mac capable of downloading the installer. If you are trying to make a bootable
Attach your newly created MacOSElCapitan10111.iso to the virtual IDE or SATA optical drive controller. Essential VirtualBox CLI Tweak (For Windows Hosts)
While Apple primarily distributes its operating systems through the Mac App Store, finding older versions like 10.11.1 can be tricky if they aren't in your "Purchased" history. mv ~/Desktop/ElCapitan10
: When setting up a new virtual machine, select "Apple Mac OS X" as the operating system type and "OS X El Capitan (64-bit)" as the version. Mount your new ElCapitan.iso file as the virtual optical drive before booting the VM for the first time.
hdiutil create -o /tmp/ElCapitan -size 8000m -volname ElCapitan -layout SPUD -fs HFS+J
: Open your web browser and navigate to the official Apple Support document titled "How to download and install macOS".
Double-click InstallESD.dmg to mount it. It will appear as a volume named “OS X Install ESD”.