I got my Mac book Pro back from service and of course I tried booting Elementary OS from USB that was made with Unetbootin and boots on Lenovo x220.
First boot resulted in ACPI PCC probe failed. Googled it and found solution to hit e key in grub menu and add nomodeset in kernel parameters. Tried again and this time I get busybox terminal after this message:
(initramfs) unable to find a medium containing a live file system
Any ideas what might be the cause of this?
Edit: Elementary OS installed on Virtual Box in El Capitan installed and booted without a hick.