I installed Ubuntu 14.04 (dual boot with Win 7) and it was working fine. But suddenly one fine day I can't login to my user account, when I log it just flashes and then it goes back to the login screen. But the odd thing is that I can log with the guest account.
I have 2 accounts one owner account/user account and another one created for the installation of Oracle. Only the guest account can login.
From the login screen, I have pressed Ctrl+Alt+F1 to get to a prompt, and login but the same thing happened there too, I entered the correct username and credentials but it flashed and goes back to the login screen.
Best Answer
This happened to me a couple of times too, this is probably because there is little space on your machine or an issue with LightDM or Xauthority but most probably xauthority. Here is what I did;
I simultaneously pressed Ctrl+Alt+F1, Login with your user name and password, and enter following command:
then
After that try again.