If you just cannot get atd to start running check the permissions on your /var/spool/cron/atjobs and /var/spool/cron/atspool directories. The should be `chmod 770` and then `chmod +t`. Also they should be owned by `daemon:daemon`.

I was getting this error when attempting to set new at jobs:

Can’t open /var/run/atd.pid to signal atd. No atd running?

If I tried to start the daemon through the service management I was getting:

sudo service atd start start: Job is already running: atd

But running `ps -elf | grep ‘atd’` yielded no appropriate results.

When trying to start the atd daemon manually on the command line I was getting:

simon@forge:~$ sudo atd -d Cannot change to /var/spool/cron/atjobs: Permission denied

Which finally gave me the clue!