My Mac Mini won't go to sleep For some reason my mac mini refuses to start the screensaver or go to sleep unless I put the mouse into a hot corner. Energy saver is set to 3 mins as is system sleep. Any ideas would be greatly appreciated.  i have included a PMSET -G result but  don't really understand it. Many thanks. (Mac Mini, 2.5Ghz intel, 4GB RAM,  10.7.5)

AC Power        -1*
Currently in use:
hibernatemode   0
disksleep   10
womp        1
networkoversleep    0
sleep       5
powerbutton 1
ttyskeepawake   1
hibernatefile   /var/vm/sleepimage
autorestart 0
panicrestart    157680000
displaysleep    3 (imposed by 181)
To debug this, you'll need to open terminal.app and look at the power assertions log. It's pretty verbose, but it really shows what's going on to prevent a sleep from happening.

pmset -g assertionslog


If you need a smaller set of data to look at, just ask for the current status and not an ongoing log of what's set and what's changing.

pmset -g assertions


You can close the window when you're done with the tools.