Some Mac computers can conserve energy using the standby feature. When your Mac goes into standby mode, it saves your current session—your open applications, files, and windows—to your hard drive. Your Mac also turns off some of its hardware systems to save power.
If you have a Mac notebook, standby lets it stay asleep on battery power longer. A notebook with a fully charged battery can remain in standby mode for up to thirty days without being plugged in to power.
Mac models that can use standby
- MacBook (2015 and later)
- MacBook Pro (2012 and later)
- MacBook Air (2010 and later)
- SSD and Fusion drive versions of Mac mini (2012 and later)
- SSD and Fusion drive versions of iMac (2012 and later)
- Mac Pro (Late 2013)
Mac computers from 2013 or later enter standby after being in sleep mode for three hours. Earlier models enter standby after just over an hour of sleep. Put your Mac to sleep by choosing Sleep from the Apple () menu.
Other requirements to enter standby are different for notebooks and desktops:
- Mac notebooks must be running on battery power and disconnected from Ethernet, USB, Thunderbolt, SD cards, displays, Bluetooth, or any other external connections.
- Mac desktops must have no external media mounted (such as SD cards, USB, or Thunderbolt storage devices).
To exit standby, do any one of these:
- 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 your Mac exits standby, the system is restored to its pre-standby state. The computer returns to full operation within a few seconds.
If you leave a Mac notebook in standby long enough for the battery to deplete fully, the computer will shut down. You can still restore your computer to its pre-standby state, and any unsaved work shouldn't be lost. To exit standby after your Mac notebook has shut down, attach the computer to a power source and press the power button.
If exiting standby or waking is slow
Your Mac might seem to take longer than usual to start up, or seem slow to wake from sleep or standby. If so, make sure that the startup disk is set correctly in the Startup Disk preferences:
- After your Mac starts up, choose System Preferences from the Apple menu.
- Click Startup Disk.
- Make sure your internal drive (usually named Macintosh HD) is selected.