This bug is affecting me as well.
I have one user out of 83 who cannot log in.
Other users can log in on the same machine without a problem.
I have:
* Deleted their ~/.compiz-1/
* Reinstalled the nvidia video drivers
* Reinstalled the unity packages from http://askubuntu.com/questions/478126/unity-not-working-after-upgrade-ubuntu-13-04-to-14-04#answer-478145
* And, in a fit of desperation, I renamed their home directory and created a new home directory from /etc/skel/.
No change in behavior.
This bug is affecting me as well.
I have one user out of 83 who cannot log in.
Other users can log in on the same machine without a problem.
I have:
* Deleted their ~/.compiz-1/
* Reinstalled the nvidia video drivers
* Reinstalled the unity packages from http:// askubuntu. com/questions/ 478126/ unity-not- working- after-upgrade- ubuntu- 13-04-to- 14-04#answer- 478145
* And, in a fit of desperation, I renamed their home directory and created a new home directory from /etc/skel/.
No change in behavior.