See What Is Keeping Your Mac Awake: pmset -g assertions
List every power assertion — the named reason an app, audio stream, or screen share blocks sleep.
Run `pmset -g assertions` to list all active sleep-prevention claims and which process holds each one.
01Command
Command
$ pmset -g assertions02What it does
Every app that prevents sleep registers an assertion with a human-readable reason, so this output names the exact culprit instead of a generic 'preventUserIdleSystemSleep'. `pmset -g assertionslog` streams changes live, `pmset -g thermlog` shows thermal throttling, and `pmset -g batt` gives a battery discharge estimate. Combine with `log show` filtering sleepCoordinator for the full sleep/wake story.
03Risk
04Undo
✓No undo needed — this command does not change persistent state.
05Sources
- macOS pmset — power management settingsEvidence: Documents pmset -g assertions and related power management queries.
Last verified: 2026-09-17 · Category: System & Settings