I got this box with a keychain password prompt, I just hit cancel and it let me proceed with the update. It sort of surprised and made me afraid I was going to get locked out. I bought my late 2013 retina macbook pro 15 from ebay, but I reformatted and reinstalled Yosemite on it, so i started from scratch with it. what is the keychain password prompt? do I need it? I really don't like all these passwords, in the end, the only person they will seem to protect from is me the user, or I end up locking myself out of my machine, I prefer as few passwords as possible, I don't keep sensitive documents on a portable computer such as my laptop.