MacOS – Previous Shutdown Cause: -2

We have a new Mac Pro (3.6 GHz) running MacOSX 10.9.3 that unexpectedly powers off.

We've taken it in for service twice and the Geniuses were not able to reproduce the issue and the hardware diagnostics didn't apparently turn up anything of interest.

If left running overnight it will often (usually?) be OFF in the morning (not asleep, OFF).

Here are the values of the power management settings (this doesn't mean much to me):

$ pmset -g
Active Profiles:
AC Power        -1*
Currently in use:
 standby              1
 Sleep On Power Button 1
 womp                 1
 autorestart          0
 hibernatefile        /var/vm/sleepimage
 darkwakes            1
 gpuswitch            2
 networkoversleep     0
 disksleep            10
 sleep                1
 autopoweroffdelay    14400
 hibernatemode        0
 autopoweroff         1
 ttyskeepawake        1
 displaysleep         15
 standbydelay         10800 

And here are the final lines I see in Console for the most recent failure, earlier today (edit: moved longer console snippet to gist because was over the limit for SE):

https://gist.githubusercontent.com/anonymous/23d25bfc9e354bd2864b/raw/cd586347b041a1f3dee6ef46628983922a44e5da/Mac_Pro_Log_Unexpected_Power_Down

I have just discovered the pmset -g log command so here are the contemporary lines from that:

6/11/14, 10:09:59 PM EDT WakeRequests           PM scheduled RTC wake event: SleepServiceImmediate inDelta=3543.05                    
6/11/14, 10:10:15 PM EDT Assertions             PID 17(powerd) Created InternalPreventSleep "Network wake delay proxy assertion" 00:00:00  id:0xe00000aa7 [System: SRPrevSleep kCPU]              
6/11/14, 10:10:15 PM EDT com.apple.sleepservices.sessionStarted SleepService: window begins with cap time=86400 secs                                  
6/11/14, 10:10:15 PM EDT DarkWake               DarkWake [CDNPB] due to ETH0/Network: Using AC                              45 secs   
6/11/14, 10:10:15 PM EDT Assertions             PID 17(powerd) Created InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:00  id:0xe00000aa9 [System: PushSrvc SRPrevSleep kCPU]             
6/11/14, 10:10:25 PM EDT com.apple.sleepservices.sessionTerminated  SleepService: window has terminated.                                                  
6/11/14, 10:10:25 PM EDT                        Summary- [System: SRPrevSleep kCPU] Using AC                                          
6/11/14, 10:10:45 PM EDT Assertions             PID 17(powerd) TimedOut InternalPreventSleep "Network wake delay proxy assertion" 00:00:30  id:0xe00000aa7 [System: SRPrevSleep kCPU]             
6/11/14, 10:10:45 PM EDT Assertions             PID 17(powerd) Released InternalPreventSleep "Network wake delay proxy assertion" 00:00:30  id:0xe00000aa7 [System: SRPrevSleep kCPU]             
6/11/14, 10:11:00 PM EDT Assertions             PID 17(powerd) TimedOut InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:45  id:0xe00000aa9 [System: SRPrevSleep kCPU]             
6/11/14, 10:11:00 PM EDT Assertions             PID 17(powerd) Released InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:45  id:0xe00000aa9 [System: SRPrevSleep kCPU]             
6/11/14, 10:11:00 PM EDT                        Summary- [System: No Assertions] Using AC                                             
6/11/14, 10:11:00 PM EDT Sleep                  Maintenance Sleep: Using AC                                                           
6/11/14, 10:11:02 PM EDT SlowResponse           PMConnection: Response from com.apple.apsd is slow (powercaps:0x0)                    1996 ms       
6/11/14, 10:11:02 PM EDT WakeRequests           Clients requested wake events: [proc=mDNSResponder request=Maintenance inDelta=7198] [proc=SleepServicesD request=SleepService inDelta=3598] [proc=UserEventAgent request=TimerPlugin inDelta=7882 info=com.apple.EscrowSecurityAlert.daily]              
6/11/14, 10:11:02 PM EDT WakeRequests           PM scheduled RTC wake event: SleepServiceImmediate inDelta=3598.04                    
Sleep/Wakes since boot at 6/11/14, 4:37:17 PM EDT  :242   Dark Wake Count in this sleep cycle:241

Time stamp                Domain                Message                                                                     Duration    Delay     
==========                ======                =======                                                                     ========    =====     
UUID: (null)
6/12/14, 5:17:22 PM EDT  Start                  powerd process is started                                                             
6/12/14, 5:17:22 PM EDT                         Summary- [System: No Assertions] Using AC                                             
Sleep/Wakes since boot at 6/12/14, 5:17:22 PM EDT  :0   Dark Wake Count in this sleep cycle:0

The Geniuses hinted that the reason that they might not be able to reproduce the issue could be due to an interaction between the PowerMac and one or more peripherals devices.

Currently connected devices are:

• older Apple Cinema Display (with DVI to Mini Display Port converter)
• Apple Optical Drive (USB)
• Apple Keyboard (USB)
• Apple Optical USB Mouse

UPDATE:

• This issue is still persisting under 10.9.4

• The running this diagnostic, suggested by Buscar:

syslog -k Sender kernel -k Message CSeq 'n Cause: -' | tail | awk
'/:/{$4=""; print}'

I get this result:

Jun 25 10:54:41  kernel[0] <Debug>: Previous Shutdown Cause: -2
Jun 25 17:51:57  kernel[0] <Debug>: Previous Shutdown Cause: -2
Jul 1 11:55:50  kernel[0] <Debug>: Previous Shutdown Cause: -2