Mac – Why won’t the Mac Pro wake from sleep at the scheduled time

mac proschedulesleep-wake

I have a 2007 Mac Pro (running Lion) that has been on the same schedule for a long time; it is set to go to sleep at 1am, and wake up at 7am. Recently, it sleeps through its wakeup time. If I press any key or anything, it wakes up immediately – and I notice the clock is off (it quickly corrects itself). It is as if when it is asleep, it is no longer keeping time, and doesn't know when to wake up. Could this be a dead button-battery inside? I thought these were only used if no AC power was present (it always has power).

Best Answer

Try resetting the System Management Unit (SMU); the SMU is typically responsible for tracking when your Mac is scheduled to wake up.

With regard to your Mac Pro appearing not to keep time, this is not a problem. It is expected behaviour for the menu bar clock to update a few seconds after your Mac has woken up.

The process controlling the clock needs to get a change in time notification before updating; it will not match your Mac's internal clock immediately upon waking up.

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MacOs – Disabling Stand By Mode on Retina MacBook Pro for Better Power Management

To disable deep sleep, run the following command in Terminal:

sudo pmset -a standby 0

This is a description of "standby" (deep sleep) from the pmset man page:

 standby causes kernel power management to automatically hibernate a
 machine after it has slept for a specified time period. This saves power
 while asleep. This setting defaults to ON for supported hardware. The
 setting standby will be visible in pmset -g if the feature is supported
 on this machine.

 standby only works if hibernation is turned on to hibernatemode 3 or 25.

 standbydelay specifies the delay, in seconds, before writing the hiberna-
 tion image to disk and powering off memory for Standby.

Battery savings depend on how much time your Mac spends in standby. While in standby mode, your Mac consumes 0 power, it's as if it is shut down (note: not taking Power Nap into consideration).

My personal recommendation would be to set the "standbydelay" value to something bigger. 2 hours, for example. This means that if you open the lid back in less than 2 hours, your Mac would be in regular sleep and wake up instantly. If longer than 2 hours, your Mac would enter standby mode and consume no power, and waking up will take a bit longer.

Example for 2 hours:

sudo pmset -a standbydelay 7200

MacOS – Why does the MBP sleep on Mountain Lion and often not wake up

I had a similar problem with my late 2012 MacBook Pro. It wouldn't wake after a long sleep: black screen but system running (I could access it via SSH).

Before trying any solution, I recommend you to reset the SMC and check if the problem persists. Also run pmset -g in Terminal (it won't change or break anything) and take note of your current settings.

I solved this problem disabling hibernation, which was introduced by Apple with a firmware upgrade. I did this by running this command in Terminal:

sudo pmset -a autopoweroff 0

To reset the original setting:

sudo pmset -a autopoweroff 1

The autopoweroff option is undocumented by Apple (doesn't appear in man pmset); it seems to be related with the "Deep Sleep" mode.

Best Answer

Related Solutions

MacOs – Disabling Stand By Mode on Retina MacBook Pro for Better Power Management

MacOS – Why does the MBP sleep on Mountain Lion and often not wake up

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