This has been going on for the past few weeks now. When I close the lid, it doesn't sleep. When I click 'sleep'…it doesn't sleep. I googled what could be the problem. I found an article that told me to go in to Terminal, Type in pmeset -g assertions . I clicked enter, and it says "PreventSystemSleep 1". Meaning a program or something is preventing my Mac from sleeping. How do I kill the program to enable my mac to sleep? What is a code i can type in to terminal to kill it? Nothing is open. All apps are closed. One way I bypassed this was resetting my SMC. It works, but it's only temporary. What can I do? Here is the article. But it doesn't tell me the kill command. http://www.adeepbite.com/lion-seems-having-insomnia-it-doesnt-sleep-easily/ Ofcourse, as soon as I post this I figure out the problem. Sorry everyone. Fixed it.