iMac won't shut down per schedule

Question

Wife's 2007 24" 2.8 ghz 6GB RAM running SL, and now Lion.

For the past month or so, It won't automatically shut down at night per the schedule in System Prefs/Energy Saver pane. My wife may not use the iMac for several days at a time, and then use it daily for a week or more - very random.

I've changed the settings by minutes, by hours. I've Safe booted.

I will try logging her out and logging into my account tonight to see if it performs there.

I do have a current clone and TM backups on an external drive.

Other than a complete reinstall of SL then Lion, what prefs are there and where are they that I could delete and re-establish to fix this problem?

Answer 1

Try an SMC reset and see if that helps.

You could also try using the pmset command in a shell (Terminal).

Answer 2

Don't know why this worked, but it did.

Logged out of my wife's account and into mine, and waited. It shut down per schedule. Booted into wife's account and reset shutdown for later.

It shut down per new schedule.

Answer 3

Followup:

Thought it was fixed, but it is not. Yesterday the iMac wa booted automatically into my wife's account. Scheduled to shut down at 10 PM. It was still sleeping at 10:30.

Don't understand why it worked when wife was logged out and I was logged in, but not when she is logged in. That usually means a preference problem in her account, but which one?

Will try a SMC fix and report back.