Aborted X-Windows Login

Problem

When I log in at an X-Windows machine, I immediately get put back at the login screen.

Symptoms

You correctly type in your username and password (i.e, you were not told "Login incorrect"). The screen refreshes itself, and then presents you with the "Maths Institute" login screen again.

Reason

The probable cause is being over quota. Unix disk quotas are set up with two limits, a soft limit and a hard limit. The hard limit can not be exceeded, while the soft limit can only be exceeded for a grace time period of 7 days. Typing quota -v (or just quota on Linux PCs) will list your current quota usage and, if you're over your soft limit, your grace time remaining.

If you have reached your hard limit, or you are over your soft limit and your grace time has expired, you will be unable to write any more data to your home directory until you get your quota back below the soft limit. The login routine on X-Windows requires that a user be able to write files to their home directory. If this is not possible, then the login procedure will fail.

Cure

Log into your account from a text-only "telnet" terminal (machines like these can be found in rooms T14, DH12 and DH28 amongst others). Type quota -v to check your quota usage. If you are over quota, and your grace time has expired, see help with disk quotas for advice on getting your disk usage back below your soft limit.