Impossible to log in my session

[PuckyPotts]

Hi everyone!

I have a surprising issue: I can't log in my session on Kubuntu 14.04 LTS. I can log withou any issues on the Guest session. When i enter my password, the authentication field vanishes and then I stay block indefinitely on the blue screen of Kubuntu. The loading icons don't even appear.

I have used a lot lately a live system: the last version of Kali Linux. I used to access my documents on my Kubuntu partition, including my documents on this session, in the /home. I can still access to all of these documents from my live version. Before the problem appears, I was doing a lot of forensics on an image on this session, but I don't think it can be related.

This is my problem, I hope somebody has an idea about the origin of my problem.
Thanks for you help,
PuckyPotts

[Snowhog]

Before the problem appears, I was doing a lot of forensics on an image on this session, but I don't think it can be related.

Highly unlikely it isn't related. What type of forensics were you doing, and were you using graphical applications run by root?

[PuckyPotts]

I was doing memory forensics. And I only use volatility frameworks, the last version (2.6). I have used on the image on my session I was studying the plugins imageinfo, pstree and memdump. I was root. Those were the last things I have done before loosing my access to my session.

The rest of the afternoon I have worked on images directly on my USB.

[Snowhog]

While doing memory forensics "as root", did you make any changes; write output to disc? If 'yes', where any such changes on files within your users (non-root) /home directory?

[PuckyPotts]

I have added, modified or removed many files on my session (non-root /hom directory) directly from Kali the last three weeks, but this morning I had no problems to log in my session. I don't remember doing any of these modifications this afternoon, only on my usb drive.

I connect through the Ctrl + Alt + F1 way.
First of all, I have an error :

E: Unknown Error: '<class 'KeyError '>' ("The cache has no package names 'wine-devel-i386'") run-parts: /etc/update-motd.d/90-updates-available exited with return 255

However, I am connected to my sessions. By list the file at the root of /home, I have three interesting files that weren't here before and I am thinking there are related to this problem:

janv. 19 22:10 .Xauthority
janv. 19 22:11 .xsession-errors
janv. 19 21:40 .xsession-errors.old

The times of the files correspond to my last attempts to log on graphically (thus the X). Have you encountered such a case before ?

[Snowhog]

Who 'owns' .Xauthority? It should be your non-root user. If it is owned by root, that could be an indication of the cause of your problem.

[PuckyPotts]

No, it is own by the non-root user :/ .

[PuckyPotts]

But those three files hqv strange righ. They all have the rights:
"-rw------"

There is an issue here? It should alo "rw" for the user?