Ever since I began using computers running OS X Lion, I’ve been having a minor— but frustrating—issue. About one third of the time I put either my Mac mini or MacBook Pro to sleep, they will not actually go to sleep. I have never been able to pinpoint what it is that’s preventing my computers from sleeping…until now.
I did some Apple forum research, and discovered that quite a few other Lion users are having this same issue. There were all sorts of suggested solutions, none of which worked for me. I finally came across a Lion user who combined a nice little GUI to a helpful Terminal command, creating an application called Sleep Check.
Sleep Check essentially makes use of the Terminal command “pmset -g assertions” and the command shows certain power assertions that, when active, will prevent system with Lion from sleeping. One example of these power assertions is Internet Sharing, which allows you to share the internet connection on one computer with another computer or device.
While the coding in Terminal can be incomprehensible to the average user, Sleep Check adds a very simple, but pleasant interface to the power assertions command, informing you exactly what is preventing your system from sleeping, and how to disable it. When these conditions have been disabled, Sleep Check will finally put your Mac to sleep.
Sleep Check is a very small, unobtrusive application that takes up about 211KB of hard drive space, can be downloaded here.
As always, I’m anticipating a software update from Apple at some point that will resolve this issue.