Permission denied: I can no longer access my files

I can no longer read or write to my files and none of my applications work. Typing ls returns permission denied.

If you have left yourself logged in for over 18 hours on a DICE machine remotely via ssh, or logged in at the front but are not using the gnome-screenlock, then your AFS and kerberos credentials will have expired.

Instead of logging out, run the command renc. This will renew your credentials. (The command will prompt you to re-enter your password.)

Always use a screensaver on DICE - it will automatically renew your credentials when you enter your password to unlock the screen.

To find out more read What is Kerberos?