The pmset command in plain English
macOS has a built-in command, pmset, that reports all the reasons your Mac currently will not let its display sleep, or go into system sleep. The output is dense, jargon-heavy, and not really meant for people. Why Won’t You Sleep runs this utility for you and translates the answer into a list of plain-English explanations: which app or system process is holding a sleep assertion, what kind of sleep it’s blocking, how long it’s been doing so, and what you can do about it.
Requirements: macOS 14 (Sonoma) or later. Apple Silicon or Intel Mac.
This is the first public beta. Future versions will arrive in place via Sparkle — no need to come back here for new builds. Feedback on what reads wrong or which processes the app can’t yet explain: feedback@whywontyousleep.app.
How to use it
- Launch the app. It reads
pmseton open; hit Refresh (⌘R) any time to re-check. - Summary tab. Each kind of sleep — display, idle system, all system — gets its own collapsible section. Green check = not blocked. Orange triangle = something’s holding it awake, with the process, how long it’s been held, and a one-line explanation of what to do.
- Details tab. The raw
pmset -g assertionsandpmset -goutput, color-coded so blocking types stand out. Selectable and copyable for sharing in a bug report. - “Where to look next” links jump straight to the right System Settings pane — Lock Screen, Battery, Bluetooth, Sharing — or open Activity Monitor with the suspect PID copied to your clipboard.
Why this exists
Every Mac user has had the moment when you walk away expecting your Mac to go to sleep. Yet, when you return hours later, the screen is still on! The answer can be found pmset output, but to read that you need to know what PreventUserIdleDisplaySleep means, why coreaudiod is involved when nothing is playing, and which legacy assertion types are still surfacing from old apps. Why Won’t You Sleep does that work and tells you, in a sentence, what’s actually going on.
Feedback wanted
If you try it and a process shows up that the app can’t explain, or a phrasing reads wrong, please email feedback@whywontyousleep.app. Real-world output is what makes the explanations more useful.