Why would a macbook running OS X 10.7.5 boot up on its own at the same time every night? The macbook was turned of around 10:22PM.  At 12:00:09 sharp it boots up on its own.  This happens every night even though the user turns off the machine at around 10PM every night.  

Why would this automatic boot be happening? Is there a way to disable it?
Lets find out

Launch the Terminal and type the following at the command line:


  syslog |grep -i "Wake reason"


The simplest reason is you have the set up in Wake up doing it :)

Check it in system preferences > Energy Saver > Schedule :):