Sleep and Power ManagementApril 22, 2007
About four weeks ago I bought my nice new black MacBook and generally I’m petty pleased with it. Though I do have a couple of niggles. Here’s one of them.
The MacBook developed a problem (no idea how) where it wouldn’t sleep. No matter what settings I used or tossing the Login Window .plist I still couldn’t make it sleep, unless I did it manually. The battery would be down to around 10% after the Mac being left unplugged over night. So I threw the Login Window .plist again, nothing.
Clearly I was wrong in thinking that the Login Window controlled the Sleep function. I changed the settings in the Energy Saver preference pane and gave it a restart. After logging in and waiting, the Macbook slept. I did a quick search for files modified that day and there it was inside the SystemConfiguration folder… In the top level Library
MacintoshHD / Library / Preferences / SystemConfiguration / com.applePowerManagement.plist
So the Power Management settings are global for the Mac and not specific to an account. To confirm this I logged into my other account and changed the sleep settings there, logged out and that change had been reflected in my usual account.
I compared one version of PowerManagement.plist from a two day old back up (it’s the weekend) with the one currently active on my system using TextWrangler. There was only one difference detected. It was in line 31, and the difference was only an integer value determining how long the computer should wait before sleeping. Clearly something else is affecting sleep, not just this plist. More digging required…