MacBook Pro: Systems waking up while lid is closed, not sleeping properly -- another fix

We continue to report on a series of issues where the MacBook Pro does not go to sleep properly, or does not stay asleep when the lid is closed. This issue is typified by the system fans remaining on and the sleep light not pulsating while the MacBook Pro's lid is closed. Generally the system will be very hot to the touch when this occurs.

Several fixes for the issue, including modification of Energy Saver settings, disconnecting external devices and more were outlined in the previous report, and we've now identified another fix, as follows:

1. Navigate to /Library/Preferences/SystemConfiguration/ (this is the Library folder at the root level of your hard drive, not the one inside your home user folder)
2. Open the file com.apple.PowerManagement.plist with a text editor like BBEdit or Apple's included TextEdit.
3. Scan for the line of text that reads ""Wake On Clamshell Open"
4. Change the "1" in the line of text below to "0"
5. Save the file (you will have to enter your administrator password to do so), then restart your Mac.

This fix works because, in some cases, MacBook Pros appear to be inadvertently waking up while the lid is closed because of a false trigger.

Note that after making this change you will have to press any key after opening your MacBook Pro in order to wake it up.

For more coverage, see our MacBook Pro special report.

Feedback? Late-breakers@macfixit.com.

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