Taming MacBook Pro Sleep with pmset Power Management

Inspecting Configuration#

Important terminology:

• Sleep: keep RAM powered
• Standby: write RAM contents to disk and power RAM off
• Hibernate: “sleep mode” in the generic sense; the actual behavior (sleep vs. standby) depends on configuration

View the currently effective configuration:

View user configuration:

Some processes may prevent standby; these will show up in the current effective settings, so they may differ from the user configuration.

Here’s a reference table:

If pmset -g custom output is missing some properties, your device simply doesn’t support them.

You can’t just go by the literal meaning of these properties—many work in combination. A few important notes:

• sleep: Even if the sleep timer has expired, the Mac may not actually sleep. For example, an active display can block sleep. All conditions must be satisfied before sleep occurs. On M1 MacBooks running on battery, the default sleep=1, which effectively means the display sleep timer (displaysleep) controls when the machine sleeps.

• hibernatemode: Whether RAM is actually written to disk also depends on standby and autopoweroff.

  • 0: pure sleep. RAM is not persisted; if power is lost, unsaved data is gone.
  • 25: pure standby. Each time you sleep, RAM is written to disk and RAM power is shut off. On wake, RAM is restored from disk. Wake is obviously slower.
  • 3: hybrid mode—sleep first, then transition to standby.

• tcpkeepalive: Disabling this in the CLI triggers a warning because it affects core system features such as Find My Mac. In practice, its impact on battery is small; disabling powernap alone is usually enough.

• standby/autopoweroff: These appear to behave the same, but originated in different contexts. standby was added to extend MacBook battery life; autopoweroff was added so desktops could meet EU energy regulations, so MacBooks don’t expose it.

Changing Settings#

Run sudo pmset restoredefaults to reset to defaults.

You need sudo privileges to change settings.

The general syntax is:

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pmset [-a | -b | -c | -u] [setting value] [...]

• -a: apply to all power profiles
• -b: apply on battery power
• -c: apply when connected to power adapter
• -u: apply when on UPS power

If pmset -g custom output doesn’t list a certain profile, your device doesn’t support it.

Some useful examples:

• Disable Power Nap on battery (recommended): sudo pmset -b powernap 0
• Disable TCP connections on battery (may break some system features): sudo pmset -b tcpkeepalive 0
• Force full standby on battery (persist RAM to disk and power RAM off): sudo pmset -b hibernatemode 25

Analyzing Wakes#

View the number of sleep/wake events since boot:

The output fields:

View detailed background wake logs:

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pmset -g log | grep -e "Wake from" -e "DarkWake" -e "due to"

The output can be hard to read.

• AOP.OutboxNotEmpty spu_queue_overflow_ep42: occurring every 1–2 hours is normal

View sleep assertions:

Sometimes the system or apps prevent sleep; these runtime locks are called assertions. They are reflected in the live power settings (pmset -g) and can also be listed explicitly. Example output:

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Assertion status system-wide:
2
   BackgroundTask                 0
3
   ApplePushServiceTask           0
4
   UserIsActive                   1
5
   PreventUserIdleDisplaySleep    0
6
   PreventSystemSleep             0
7
   ExternalMedia                  0
8
   PreventUserIdleSystemSleep     1
9
   NetworkClientActive            0
10
Listed by owning process:
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   ........

The numbers represent whether each type of lock is active, not how many locks of that type exist. Below that, you’ll see which process owns each assertion and whether it has a timeout. Typically UserIsActive and PreventUserIdleSystemSleep are both active:

• UserIsActive: a system process tracking user activity, with a 120‑second timeout
• PreventUserIdleSystemSleep: a system process holding this lock while the screen is on; it’s released automatically once the display sleeps.