

The development of the old versions is discontinued.
DISK SENSEI EL CAPITAN INSTALL
I booted into internet recovery and attempted to re-install OS X El Capitan, however going through the prompts I reach a dead end where it asks me to 'Select the disk where you want to install OS X'. Give the drive a name or keep it the same, and under Format choose OS X Extended (Journaled), then click on Erase THIS ERASES EVERYTHING ON THE MAC. This raises some red flags, as her internal 256 GB hard drive is nowhere to be found in disk utility.
DISK SENSEI EL CAPITAN MAC
Select Macintosh HD (or whatever the name of the target Mac drive), then click on the Erase button. Requirements: Intel-based Mac or Mac with Apple silicon using macOS Ventura 13. At the OS X Utilities screen, select Disk Utility. DiskMaker X will open a boot disk options dialog window select El Capitan. Use the correct version, and don't try to use a version intended for an earlier operating system. Try another USB port and wait 10 sec again. If it does not detect it after 10 sec and you only see your hard-drive. Mount toggles to Unmount for volumes that are available in the Finder. Start your Mac, press immediately OPTION (aka ALT) Select the Orange icon (aka a USB stick) labelled El Capitan. Across the tab, you see First Aid (disk repair), Partition, Erase, Mount, and Info.

Hold down the option key, and restart the system.

Now, with the bootable disk, insert it into the system. Once you have downloaded the image files on your system, create a bootable USB disk.
DISK SENSEI EL CAPITAN ISO
Plug-in your USB key on a turned-off computer. Since the OS is fairly old, you have to download the DMG file or ISO file of the OS from an authentic source. There is a specific version of OnyX for each major version of the operating system. I created a USB disk with a bootable El Capitan as per this documentation. Heres what Ive tried so far: - Redownloading El Capitan from the App Store (if something was wrong with the first image) - Tried creating the USB on three different Macs (with Mavericks, Yosemite and El Capitan) - Tried creating the USB by using Diskmaker X 5.0.1 instead of the terminal command (on three Macs) - Formatting the USB a thousand. OnyX is a reliable application which provides a clean interface to many tasks that would otherwise require complex commands to be typed using a command-line interface. OnyX is a multifunction utility that you can use to verify the structure of the system files run miscellaneous maintenance and cleaning tasks configure parameters in the Finder, Dock, Safari, and some Apple applications delete caches remove certain problematic folders and files rebuild various databases and indexes and more.
