How can I forcibly shut down my Mac at an appointed time? I'm looking for an auto shutdown app that will forcefully shut down the computer at an appointed time.

The most important part of this is that the shutdown should not be cancelable (unless the process is extremely onerous).
Ok, so further to my previous answer, I can walk you through getting cron (a built in UNIX schedule service) to run a scheduled shutdown command for you.

It will run as root and will be forced.


Open Terminal (/Applications/Utilities/Terminal)
Input sudo crontab -e


You'll need to enter your login password and then press enter.

You'll now be in a text editor (vim). Carefully input the following keystrokes.


Press i once (this will allow you to enter text)


Let's say you want the machine to shutdown at 2am every day, we'd now enter:

* 2 * * * /sbin/shutdown -h now


If you wanted the machine to shutdown at 2:30am every day, you'd enter:

30 2 * * * /sbin/shutdown -h now



When you've typed this in, press esc
Then press shift+z shift+z (that's uppercase "z" twice, to writes the changes and quit the editor)


You should now be dropped back to the command line where you started.

You're done!