From time to time, customers come in with a general issue that their laptop or desktop doesn’t ‘sleep’ when they tell it to. Occasionally, I’ve seen this on my own computers since I switched to a Mac. Sometimes, it can be an actual hardware malfunction, but most of the time, there is something within the software that prevents the computer from sleeping.
I did some Apple forum research a while back about it, and found various suggested solutions — none of which worked for me. I finally came across a user who combined a nice little GUI to a helpful Terminal command with an application called “Sleep Check.”
Sleep Check essentially makes use of the Terminal command “pmset -g assertions”. The command itself lists certain power assertions in the Mac OS that, when active, will prevent the system 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 98KB of hard drive space.