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As the title says, I have problem with login. When I enter correctly password and confirm, black screen with log appears for like 0,5 seconds and then it goes back to login screen. Unlike the others, I cannot login even as a guest.

Log screen contains only few logs, last one is that battery state is [OK]. Once I have seen something like cannot find hardware rng device, but I cannot see it now.

When I go to console using Ctrl+Alt+F1, path variables are not set, although I edited them in .bashrc and .bash_profile. Is that correct? Export command solves this.

Yesterday, when I was working on computer, I have not done any changes to Unity and graphics in general. I have been changing environment variables.

Do you have any ideas what could be source of this problem?

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Next error in log found - cannot write bytes, pipe is broken. – Petr Aug 10 '12 at 9:15

I had a similar issue Ubuntu 12.04 login screen finite loop and keep end my session.

Can you check if you're using any PPA xorg-edgers packages like Version: 2:2.21.0+git20130204.9640640a-0ubuntu0ricotz~precise at xserver-xorg-video-intel?

$ apt-cache show xserver-xorg-video-intel | grep "Version"
Version: 2:2.21.0+git20130204.9640640a-0ubuntu0ricotz~precise
Version: 2:2.19.0-0ubuntu1~xup1
Version: 2:2.17.0-1ubuntu4.2
Version: 2:2.17.0-1ubuntu4

$ apt-cache show xserver-xorg-core | grep "Version"
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installing gnome-session-fallback then login in worked for me.

sudo apt-get intsall gnome-session-fallback
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