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When I try to log into my user profile, the screen turns black and then just returns to the log-in menu.

What to do?

Schould I "repair" Ubuntu. If yes, how is it done?

I can't choose to "repair" like in Windows when I boot up with the Ubuntu installation USB I got.

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Got the problem, found the answer :

  • Log into your account using a terminal, which you can reach using Ctrl + Alt + F2.
  • Look at the permissions for your .Xauthority file, using ls -la ~/.Xauthority.

It needs to be readable and writeable by your user :

-rw------- 1 you yourgroup .Xauthority

(usually, group and user are the same for regular users)

If your permissions are invalid, you can apply a fix by doing :

chown you:yourgroup ~/.Xauthority
chmod 600 ~/.Xauthority
  • Then go back to your display manager with Ctrl + Alt + F7, and try again !

  • If it still fails, have a look a your X11 logs, and share : cat /var/log/Xorg.log.0 | tail -n50

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Regarding not being able to log in on the usual Ubuntu 12.04 screen. I had this problem after installing some software. After checking that my user name owned my home directory and files such as .Xauthority I read an article about checking the main /tmp directory permissions and ownership. To my horror I found that the software package install script had taken ownership of the /tmp directory, which meant that no user could log in because they did not have permission to use the /tmp directory, which all users do require. The solution was: Press the CTRL, ALT, and F1 keys at the same time when in the usual log in screen. This takes you to a login request. Then enter your normal user name and press enter. When prompted enter your usual password and press enter. You should then be shown a line ending with the $ sign. This will take you into your home directory, for example /home/tim. Change to the main root directory by typing in 'cd /' and press the enter key. type in 'sudo chmod 777 /tmp' and press the enter key, then enter your normal password. type in 'sudo chmod +t /tmp' and press the enter key and then your password. type in 'sudo chown root:root /tmp' and press the enter key then you password. type in 'ls -l /' and press enter key. you should see in the file list the entry 'drwxrwxrwt root root The permissions are now correct. Press the 'CTRL, ALT, and F7' keys to return to the usual Ubuntu login screen. Hopefully this will now work. Tim

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