Can not get passed the login screen

Question

I have the same issue as others (see Login returns to login screen [closed]).

When I arrived at the login screen, I enter my password, the screen goes black for one second, displaying some text, and then it returns me to a fresh login screen.

I can go to a console alt+f1 and login into my account on the command line.

It is a fairly fresh install of ubuntu 12.04 64 bit, plenty of room left on the home dir. Permissions on the home directory are okay 755. Only one user.

Any hint because I cannot fix this apparently... Thanks!

Oh yes: the xsession-errors log says: "mkdtemp: private socket dir: Permission denied". Reinstalled unity, to no avail.

Solution

Check the permission bits on /tmp:

ls -ld /tmp

drwxrwxrwt 6 root root 296 May 12 10:57 /tmp
  ^  ^  ^^

Escpecially notice the w's and the t at the start of the line. If you have different permission bits, change it using:

sudo chmod a+wt /tmp

Comments

[jippie]

what does ls -ld /tmp say? It should start with drwxrwxrwt .. root root. Notice the w's and the t in rwt.

[Joachim Jacob]

Thank you very much. I changed /tmp permissions: sudo chmod a+wt /tmp

[jippie]

I'll add it as an answer so it can easily be found by others.

[Anton K]

Thanks, that helped! Any ideas how could this happen, if I did not sudo chmod a-w /tmp ?