Mac computers: About standby
Learn more about the standby feature on your Mac.
General standby information
Mac notebook and desktop computers have power standby features that conserve energy. Mac computers manufactured in 2013 or later enter standby after three hours of "regular" sleep while earlier models enter standby after just over an hour of regular sleep. During standby, the state of the computer is saved to the flash storage (SSD) and then the power to the hardware subsystems turns off to increase the length of the standby. For example, RAM memory and the USB bus are powered off during the standby.
Standby also extends how long a notebook computer can stay asleep on battery power. A notebook with a fully charged battery can remain in standby for up to thirty days without being plugged in to an AC power source.
Macs that can use standby mode
- MacBook Pro (Retina, 13-inch, Late 2012 and later)
- MacBook Pro (Retina, 15-inch, Early 2013 and later)
- MacBook Pro (Retina, Mid 2012)
- MacBook Air (Mid 2010 and later)
- SSD and Fusion drive versions of Mac mini (Late 2012 and later)
- SSD and Fusion drive versions of iMac (Late 2012 and later)
- Mac Pro (Late 2013)
Standby requirements are different for notebooks and desktops.
For a notebook to enter standby, it must be running on battery power and have no external connections (such as Ethernet, USB, Thunderbolt, SD card, displays, Bluetooth, and so on).
For a desktop to enter standby, it must have no external media mounted (SD cards, USB, or Thunderbolt storage devices).
To exit standby, do any one of the following:
- Press a key
- Click the trackpad or mouse
- Open the lid on a notebook
- Plug in a power adapter on a notebook
- Plug in a display
When the computer exits standby, the state of the system image stored on the flash storage is used to restore the system to its pre-standby state. The computer returns to full operation within a few seconds.
If you leave a notebook in standby long enough for the battery to deplete fully, the computer will shut down. You can recover your computer to its pre-standby state and any unsaved work should not be lost. To exit standby at this point, attach the computer to an AC power source and press the Power button.
If you find that your Mac computer seems to be taking longer then usual to start up or seems slow to wake from sleep or standby. If this is the case, make sure the startup disk is set correctly in the Startup Disk preferences:
- Choose System Preferences from the Apple () menu.
- Choose Startup Disk from the View menu.
- Make sure your internal drive is selected.