I recently got an older iMac from a relative. When i turn it on i get the 4 options and when i choose to install OSX Yosemite it strarts to run but after the last minute of the process the whole thing moves back to the 4 options. How to fix this?

Thinking about this little bit more, if the iMac is new enough, it might be possible to install a later version of the OS without having to make a bootable installer. Some of these iMacs that can run Yosemite can also run High Sierra. It might be worth trying this before making the installer.

How to download macOS - Apple Support

Try the High Sierra download:

If that works, you can go directly to the App Store and get High Sierra:

If this does not work, then here's the installer for El Capitan instructions:

1. Erase (Mac OS Extended (Journaled)/GUID partition) a 16 GB USB stick with the name MyVolume. 

2. Download the El Capitan full installer from the link. 

3. Double-click the downloaded InstallMacOSX.dmg in Downloads to mount the installer as Install OS X on the Desktop 

4. Start Terminal and enter (copy and paste) the following as one command and Press Enter: 

rm -rf /tmp/El\ Capitan 

pkgutil --expand /Volumes/Install\ OS\ X/InstallMacOSX.pkg /tmp/El\ Capitan 

diskutil eject Install\ OS\ X 

cd /tmp/El\ Capitan 

hdiutil attach InstallMacOSX.pkg/InstallESD.dmg -noverify -nobrowse -mountpoint /Volumes/esd 

sudo asr restore -source /Volumes/esd/BaseSystem.dmg -target /Volumes/MyVolume -noprompt -noverify -erase 

5. When it completes and returns to command prompt, enter (copy and paste) the following as one command and Press Enter: 

diskutil rename OS\ X\ Base\ System Install\ El\ Capitan 

rm /Volumes/Install\ El\ Capitan/System/Installation/Packages 

cp -rp /Volumes/esd/Packages /Volumes/Install\ El\ Capitan/System/Installation 

cp -rp /Volumes/esd/BaseSystem.chunklist /Volumes/Install\ El\ Capitan/ 

cp -rp /Volumes/esd/BaseSystem.dmg /Volumes/Install\ El\ Capitan/ 

hdiutil detach /Volumes/esd 

sudo bless --folder /Volumes/Install\ El\ Capitan/System/Library/CoreServices --label Install\ El\ Capitan 

cp /Volumes/Install\ El\ Capitan/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/InstallAssistant.icns /Volumes/Install\ El\ Capitan/.VolumeIcon.icns 

cd "$HOME" 

rm -r /tmp/El\ Capitan 

diskutil eject Install\ El\ Capitan 

20 minutes later you will have the El Capitan USB boot installer. Boot your friend's Mac from it by inserting the USB stick into the Mac and pressing/holding Option key at power-on. Select the orange Install OS X icon at the gray efi boot screen using the mouse and press Enter. It will boot (slowly) from the USB stick and take you to a recovery screen where you can choose to reinstall El Capitan to the internal HDD, use Disk Utility, and more. 

It's probably worth getting the Mac up and running first and then seeing what model it is and how far it can be upgraded. Post back if you have any issues with any of this.

It''s also good practice to run Disk Utility on the Disk and the volume before installing the new OS. You can do this from the internal Recovery HD. (Disk Utility repairs the complex software on the disk and should fix any corruption that might be present.)

Good Luck 

First of all, the iMac was likely on Yosemite because that's what the previous owner had it on and it looks like it was left with Yosemite Recovery.

"An older iMac" covers a lot of territory and several of them can run Yosemite. However, looking at Mactracker, it appears that none stopped with Yosemite. Unless you really want to install Yosemite, it might be preferable to install the latest version of the OS it can run as that might be more useful to you. (Mactracker is available in the Mac App Store.)

What model is the iMac? The model number should be on the back and would be something like "A1224". With that, we could look it up and determine the maximum OS for the iMac and what the options might be for installing it.

So please post back with the model number and we'll take it from there.

Hey there Faabx,

If reinstalling macOS didn't work from macOS recovery, following these steps: How to reinstall macOS, and creating a bootable intaller didn't help: Create a bootable installer for macOS, there may be a hardware related issue. Contact Apple Support for service options: Contact Apple Support.

Take care.

Hi Faabx,

Did you ever solve your issue? I ran into exactly the same thing recently with both Yosemite and El Capitan. It appears that only the Recovery HD was installed on the volume and the volume could not boot.

Doing an option boot, the image at the right is an external drive that I was attempting to install El Capitan on. All that appears is the 10.11.6 Recovery HD--the OS evidently was not installed.

Ultimately I was able to create a bootable installer for El Capitan on a Monterey volume that was able to install the OS on both an internal and an external drive. If you are still struggling with this, I'd be happy to help you here with some step -by-step instructions.

Hi Faabx,

Glad I was able to help! Those instructions originally came from an Ask Different posting:

https://apple.stackexchange.com/questions/379603/how-do-i-create-el-capitan-installer-on-a-catalina-or-post-el-capitan-installe

Glad the iMac was able to go as far as Catalina--that's really great!

Happy Computing!