el cap installed on all of my three macs, flawlessly, and now I'm trying to create a bootable USB disk to use it in the future , if needed, as I've done with Mavericks. I downloaded again the installer, used the Diskmaker X freeware app .... and it didn't work! Stuck at the copying files prompt. I tried with the command prompt method.... Same result ! Ok, I assumed it was the 16 Gb USB stick (strange enough , since it was the same used for Mavericks) so I buy another one. Tried again and same results. What's wrong ???