Debian Log In Failure With Correct Password

Perhaps your .profile, .bash_profile, /etc/profile, or .bashrc contains an error, and makes the shell exit?

If thats the case, use ctr-alt-F1 to enter the shell. use the command su - root to enter a root session, and then use nano or vi to edit the file that is broken.

Had exactly the issue as described. After switching to a console (Ctrl+Alt+F1 through Ctrl+Alt+F6), it appeared that the root folder was completely full (use df ). A simple sudo apt-get clean did the trick. After confirmation that the drive has space available, go back to login screen using Ctrl+Alt+F7).

I also have this problem from time to time, but the solutions here don't work. I found the following somewhere, but can't find it again, so here it is:

1. Switch to a console with Ctrl+Alt+F3;
2. Log in using the console (you are asked for your username and password right away);
3. Type sudo chmod 1777 /tmp and the password for sudo;
4. Go back with Ctrl+Alt+F7 and proceed normally.

Those are the standard permissions of /tmp and I have absolutely no clue why they should be wrong at log in. The only pattern I think I found is that I need to have tired to log in with a wrong password before using the correct one stops working.