new user can't login in Mint

Question

I have created a new user in Mint 12, with this commands:

sudo useradd irene
sudo passwd irene
//here I entered the password

But if I try to login with this user the screen goes black for a couple of seconds and then I'm back at the login screen (no error appears).
I know the password I enter is correct, because if I enter something else the "wrong password" shows up.

If you need more info or tell me what log files I should check, please tell me.
Thank you for reading.

edit: adding info
here are the results for groups for the 2 existing users (mine, which is administrator, and the one for my gf):

$ groups osdave
osdave : osdave adm dialout cdrom plugdev lpadmin admin sambashare
$ groups irene
irene : irene

I'd say I have to add irene to a group, but which one?
Also, login as irene (in console):

su irene

and moving to home, there is only 1 osdave directory: shall I create it myself?

mkdir irene

Answer 1

You need to set the user's home directory.

sudo mkdir /home/irene && sudo useradd irene -d /home/irene && sudo chown -R irene:irene /home/irene

But it's always better to use the grpahical UI to add users. If this doesn't work, what version are you using? What DE?

Answer 2

(These are generic instructions for investigating this general problem.)

There are two possibilities: either the user can't actually log in (the authentication might succeed, but starting the session fails), or something in the user's profile is causing the user's shell to exit immediately.

To investigate a system-level failure, look at the system logs, typically /var/log/auth.log. Many modern systems use PAM, so you'll see log entries from pam_something mentioning the user name. The PAM configuration is in /etc/pam.conf or /etc/pam.d/name_of_service.

To investigate a user-level failure, try temporarily moving the user's dot files to a different directory. Also, try logging in with su -p rather than on a console, as it looks like the screen is cleared immediately after your login attempt. If it looks like the user's ~/.profile is being executed and exits unduly, add set -x at the top of that file to see a trace of what it does.