I was successfully able to update my late 2011, iMac, but not on my late 2012 13" Retina MBP. Every time I try, it immediately says it has downloaded 50% then fails. I've entered my administrative password to install it, logged out, logged back in, etc. My internet connection is great.
Force quit Creative Cloud Desktop application if necessary to quit it.
You'll need to reboot your computer because that will screw it up temporarily. After rebooting, it will probably work fine.
If not, uninstall Creative Cloud Desktop, and install it again.
Tried the first several times.
Unistalling CC Desktop didn't help either.
Tried viewing the install logs as per this page: