I am running monit on a CentOS 5.3 box. Today I added a process to monitor and restarted monit via the init.d script. It did not restart. In short, when I start it, I get this:

Starting Process Monitor (monit): [ OK ]

Looks good, but it I run a "status" immediately afterward, I get "monit dead but subsys locked". Furthermore, I get no errors in the messages log, my config comes out clean if I run a "monit -c /etc/monit.conf -t", and all the monit options from the CLI work fine. I tried undoing my changes, but that didn't help. It just won't start up as a daemon.

I'm baffled. I've never had this problem before. It has been working fine on all my CentOS and ubuntu boxes up until now.

I don't have my Centos system in front of me, but /var/lock/subsys (?) is where the pid lock files are stored.
Also, have a look in /var/log/messages & put 'set -xv' at the top of the init shell script & disable any stdout/stderr redirects.
That way, you should get everything sent to the screen.

My /etc/monit.conf file had the daemon setting commented out by default. This was working before, so I don't know what changed, but once I removed the comment, it started via the init.d script normally.

set daemon 120