Installing El Capiton on an old Mac Book Pro today, I received the error:
Process: 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. El Capitan may be struggling with your Wi-Fi settings. Apple has released updates to try and improve this problem, so first check for any updates to OS X and see if you can download a solution.
OS X could not be installed on your computer
No packages were eligible for install. Contact the software manufacturer for assistance.
Quit the installer to restart your computer and try again.
I checked Appleās support Matrix (it is a very old macbook pro) at https://support.apple.com/kb/SP728?locale=en_GB and it was listed as supported.
After lots of Googling and investigation, I discovered that the date and time were not set to current, the macbook thought it was year 2000.
You can easily reset the time and date by following the steps below:
Once the Date and time are configured you will be able to install OS X.
Easy fix, for a ridiculous error!