Fix OS X that won´t sleep

I had a problem with my iMac not going to sleep. It happened just the other day, I´ve never experienced anything like it before. I run OS X Lion. If I pressed Cmd + Option + Eject the screen went black, but the disk was still running.

I searched the internet and forums, and found all sorts of solutions. Finally, I found a posting by jcarpio on https://discussions.apple.com/thread/3190738?start=45&tstart=0.

His solution is to type in a couple of commands to actually pin down the cause of the non-sleep.

Open Terminal and type in:

pmset -g

You´ll get some output, and one of the lines would probably read something like:

sleep 0 (imposed by 18)

Sleep 0 tells us that sleep is disabled because of a process with id 18. It can be any number, if you´ll get 18 in your terminal, it´s a coincident.

The next step is to find out what number 18 really is. Type:

ps -ef | grep -e 18

The | is called a "pipe", and is written by Option + 7 on the small mac keyboards.

You´ll get some input on what is is. jcarpio´s problem was his printer being shared on the network, mine was that there was a document in the print spooler, and no printer connected. I opened the print spooler, and deleted the print job, and ta-da, the problem was solved!