Cfxtrjtrk

Press Ctrl + Alt + F1 and log in there and run:

sudo chown -R $USER:$USER $HOME

Then press Ctrl + Alt + F7 and try to log in.

Look at here: Can't login to Ubuntu 14.04 after upgrade maybe can help you.

1. Check the $HOME permission and owner, chown $USER:$USER -R $HOME; chmod +x -R $HOME, or try to use a Guest Session, or try adduser to create a user then login.




2. Try reinstall Ubuntu Desktop, sudo apt-get install --reinstall ubuntu-desktop ubuntu-session.




3. If all above can't work, maybe the lightdm is break, try to fix sudo apt-get install lightdm --reinstall.




4. Or, just try to use kdm & Kde desktop: sudo apt-get install kubuntu-desktop kde-standard. (。・_・。)

I had same issue i was setting up oracle and messed up with .bashrc PATH variable, with this i could not get past the login screen. Thing that solved my issue was that, in .bashrc, I accidentally did not append $PATH: in PATH variable.

I wrote:

PATH=<other paths>

Correct format:

PATH=$PATH:<other paths>

This worked for me, if this is the case it should work for you too.

I had similar issue on fresh 18.04 install. Safemode worked well, normal mode kept kicking me out after logging in. UI also lagged during animations, so it was clear that was a graphics issue. So I just updated my Nvidia drivers and it worked.

sudo add-apt-repository ppa:graphics-drivers



sudo apt-get update



sudo apt-get install nvidia-390

Do experience any graphical glitches?

This might be the result of Unity not beeing able to start due to a problem with getting 3D acceleration - so your graphics-card driver is in question (thanks for nothing compiz).

Do you happen to know which graphics card you are using?
When in doubt you can press CTRL+ALT+F1, login, type:

lspic | grep VGA

usually you ll get something like

you@yourPc:~$ lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GK110B [GeForce GTX 780 Ti] (rev a1)

You'll then have to update your graphics-card driver, which either might be:

ATI/AMD:

sudo apt-get install fglrx

NVIDIA:

sudo apt-get install nvidia-current

Intel cards usualy don't cause problems.

If this all did not help you might consider booting an older kernel from GRUB, if any is installed.
(you can return to your graphical enviroment by pressing CTRL+ALT+F7)

I had the same problem in 16.04

rm .Xauthority // like the_Seppi said

sudo chown -R $USER:$USER $HOME // like praveen said

chmod +x -R $HOME

and a reboot

did it fore me

I had same problem with Ubuntu 18.10 and following method help me:

1. At the login screen use Alt+Ctrl+F3 to access the command line login method.




2. Log in to the shell with your username and password.



3. 
   

   Uninstall and reinstall Ubuntu lightdm. Run the following (be sure to connect to the network):

   
   
   

   sudo apt-get purge lightdm
   
   sudo apt-get install lightdm
   
   dpkg-reconfigure lightdm
   
   

   
   



4. Once reconfigured, now reboot.