Macbook Air 2011 only wakes from sleep if plugged in I've had trouble getting my macbook air (with 10.7) to wake up.  Sometimes, when I open the laptop, it doesn't wake up - no matter what buttons I press, how many times I open or close it, or what I plug in to the USB port (though I haven't tried plugging in much).

However, so far, I can get it to wake up by plugging in the power adapter.

Any idea what is causing this, or what I can do to wake it up if I don't have a power adapter handy?

EDIT: Used pmset's log to find the "bad times".  In the messages below, 12:03 was when I shut the machine, 1:13 I was asleep, the computer was sitting on its own with nothing plugged in.  7:57 was when I woke it by plugging it in; I had tried for about 10 minutes prior to that to wake it by other means.

Time stamp                Domain                Message                                                                         Duration        Delay     
==========                ======                =======                                                                         ========        =====     
UUID: 51214312-4FF5-4235-A234-06663390AD26
12/15/12 12:03:08 AM MST sleep                  Clamshell Sleep: Using BATT (Charge:84%)                                        4207 secs 
12/15/12 12:03:08 AM MST timedout               Kernel: Response from Google Chrome He timed out                                                30000 ms        
12/15/12 1:13:15 AM MST  Dark Wake              DarkWake due to EC.SleepTimer: Using BATT (Charge:83%)                          0 secs    
12/15/12 1:13:15 AM MST  slowresponse           PMConnection: Response from AirPort configd plug-in is slow (powercaps:0x19)                    277 ms          
12/15/12 1:13:15 AM MST  slowresponse           PMConnection: Response from IPConfiguration is slow (powercaps:0x19)                            278 ms          
12/15/12 1:13:15 AM MST  slowresponse           PMConnection: Response from SystemUIServer is slow (powercaps:0x19)                             283 ms          
12/15/12 1:13:15 AM MST  sleep                  Maintenance Sleep: Using BATT (Charge:83%)                                      24276 secs
12/15/12 1:13:15 AM MST  timedout               Kernel: Response from Google Chrome He timed out                                                30000 ms        
12/15/12 1:13:19 AM MST  slowresponse           PMConnection: Response from AirPort configd plug-in is slow (powercaps:0x0)                     4085 ms         
12/15/12 7:57:51 AM MST  wake                   Wake from Standby  : Using AC (Charge:83%)                                      1056 secs 
12/15/12 7:57:53 AM MST  slowresponse           PMConnection: Response from SystemUIServer is slow (powercaps:0x1f)                             1549 ms         
Sleep/Wakes since boot:70   Dark Wake Count in this sleep cycle:1
It's hard to know if this is a hardware failure or a software issue, but the first step is opening terminal and running some power management tools to see what is really happening.

 pmset -g log


The above command will dump a very long log you can save to a file by copying it or redirecting the output like pmset -g log &gt;&gt; ~/Desktop/sleep.log and looking over the times when it slept and woke properly. Perhaps it's going to have a hint what is happening when the wakes do not work.

Secondly, you could run pmset -g pslog in a second window and let it run. When you sleep and wake, it should log those power events in real time. The next time it needs a power adapter to wake you can review the events that led up to that failure. It also lets you see what's happening when you test sleep and wake.