Having had a hard drive failure, I'm attempting a clean install of Yosemite on a 2010 Mac Pro, with a brand new 120GB OWC SSD.
I've tried using a Yosemite boot disk, using both an external hard drive and a USB memory stick, which both suffered the same symptoms, and now I'm seeing something similar with an old Mavericks USB memory stick, which I believe has worked before.
The problem I had with the Yosemite install was that it would start the installation, I'd accept the terms, and it would get to the "Preparing to install" screen. It would then count down from 8 minutes, stop at "1 second remaining" for about 10 minutes, then "0 seconds remaining" for about another 10 minutes, before finally presenting the error message, "An error occurred while preparing the installation. Try running this application again."
With Mavericks, I'm seeing the same thing up to the "0 seconds remaining" problem, but then it just hangs - on the last attempt I waited about an hour, and I'm in the middle of a second attempt now.
I've tried resetting the PRAM, and checked the date in the terminal which is correct (albeit the wrong time zone, but I'm guessing that's not important).
The only entry in the Installer system log is:
localhost Install OS X Mavericks: Can not connect to /var/run/systemkeychaincheck.socket: No such file or directory
Any advice much appreciated!