RaspberryPi B using Raspian 12/24/14, and old NOOBS
I've been having the same problem as vmorley. I am unable to get past a newly appearing logon screen. I have the problem on 3 different sd cards, 2 with Raspian 12/24 and one with the old NOOBS.
One of these Raspian cards was generated with Bill Wilson's rpi-clone, and the NOOBS card copied with win32 diskimager. I still have two old NOOBS cards that boot into the desktop ok. I have no Idea how these 3 cards got changed.
As a 74 year old Linux Noob, I've become nearly convinced that I don't have enough time or neurons left, to keep screwing with this moving got'cha. Its' been a steep learning curve thus far. I had succeeded in installing CUPS, to printing a test page on my Cannon All-in-one.
On those logon screens I was unable to login to pi, but could get into a "practice user" that I had established. It went to the desktop. Unfortunately, I had not yet learned to assign it any privilege, so it was useless.
After browsing these forums for many hours, tried to reset the pi password by appending "init=/bin/sh" and then trying "init=/bin/boot" in cmdline.txt. No help, deleted these appendages.
Update: Problem solved.
I had read vmorley's posts several times before realizing that my problem was identical. The topic title did not initially connect with me, as I had not setup a terminal, and little idea of a VNC server.
In summary; his fix worked for me. I would add only one thing: To his sentence "Then set boot preferences", I would insert "(in raspi-config)" for the Noob like me.
I'm wondering at this point as to whether my problem may have resulted from not specifying boot options in Bill Wilson's excellent raspi-clone.