macOS won’t sleep from the Apple menu

Especially with an external monitor

April 20, 2023

This one has been bugging me for a while now and I’m so glad I finally found the cause.

It was so stupid: when I clicked Sleep in the Apple menu to manually put my Mac to sleep, I was leaving my fingers on the trackpad for a fraction of a second, and that “trackpad activity” caused it to instantly wake up! 🤦‍♀️

If that was your issue as well, enjoy, you can stop reading here. In case you’re bored though, here’s the full story.

External monitors, laptop lid, and sleep

Before I got my external monitor, I was never putting my Mac to sleep explicitly. I just closed the lid and that was it.

But with an external monitor connected, it’s another story.

This goes back to 2011, with Mountain Lion. Before then, on Snow Leopard, closing the lid of your MacBook was putting it to sleep, regardless whether or not an external monitor was connected. Since Mountain Lion though, doing so puts your MacBook in clamshell mode, where the external screen becomes your primary monitor!

There’s essentially two groups of people when it comes to closing the laptop with an external screen connected: the ones who want it to sleep and the ones who want it to go in clamshell mode.

To be fair I could see myself leaning one way or the other depending on what I want to do! We can’t have both at the same time, and the option that’s not the default will have added friction.

When sleep was the default and you wanted to close your lid to go in clamshell mode, you had to:

  1. Close the lid and let your laptop go to sleep.
  2. Wake it up with your external mouse/keyboard.

With clamshell being the default, if you want to sleep, you have to:

  1. Unplug the monitor.
  2. Close the lid.
  3. Plug the monitor again if you were also charging through it.

Or even better:

  1. Click Sleep in the Apple menu.
  2. Close the lid.

That last one is acceptable to me, except at first, it didn’t seem to work!

Waking up right away after manually sleeping

After clicking Sleep in the Apple menu, both screens would turn off for like a second, and then they would come right up!

Usually after trying a couple times, it would actually go to sleep, but I could never really understand why. This exactly what’s described in this Apple support thread although it got locked for inactivity before ever being resolved. It just links to a Apple guide about diagnosing sleep issues with some generic advice but nothing useful to our case.

The other day though even after 10 tries, it kept waking up right away, so I decided to dig into it.

The technical symptoms

When we look at the Activity Monitor app, I discovered we can show additional columns by right clicking on the columns header. In there, we have Preventing Sleep.

Activity Monitor column settings

In my case, it was WindowServer, aka the macOS process responsible for managing windows, as well as powerd:

Processes preventing sleep

Note: the Energy tab in Activity Monitor is also useful to diagnose sleep issues! Not only it displays the power consumption details of the currently running apps, but also of the ones that were previously closed! And you can directly see if they’re preventing sleep or not.

In our particular case though it wasn’t as useful as the CPU tab because it doesn’t show the system processes.

Moreover, we can use the pmset command (power management settings) to list if anything is preventing sleep (emphasis mine):

$ pmset -g assertions
Assertion status system-wide:
   BackgroundTask                 0
   ApplePushServiceTask           0
   UserIsActive                   1
   PreventUserIdleDisplaySleep    0
   PreventSystemSleep             0
   ExternalMedia                  0
   PreventUserIdleSystemSleep     1
   NetworkClientActive            0
Listed by owning process:
   powerd: PreventUserIdleSystemSleep named: "Powerd - Prevent sleep while display is on"
   WindowServer: UserIsActive named: " service:AppleHIDKeyboardEventDriverV2 product:Apple Internal Keyboard / Trackpad eventType:3"
	Timeout will fire in 600 secs Action=TimeoutActionRelease

Researching the symptoms

Again, we saw that powerd and WindowServer are the culprits.

Looking for those leads us to a thread on Apple support about WindowServer preventing sleep mode, but without any proper resolution: the problem just seems to have gone away for some people with an Apple update, but the messages are from a few years ago, and in my case I’m running the latest version of macOS.

We also find two Reddit threads, one for WindowServer and one for powerd, again both without a clear resolution.

Note: The WindowServer thread has unrelated resolutions where sharingd and coreaudiod were preventing sleep, which is not what we’re looking for here. That being said if you’re currently sharing files over the network, or you have music playing, this will prevent your Mac to sleep, so look into this first!

On top of that, I’m a bit dubious that powerd and WindowServer are the problem here. After all, “preventing sleep while display is on” sounds like a very reasonable thing to do, as well as preventing sleep when there’s activity on the keyboard/trackpad! And it would be logical to expect that manually putting the system to sleep would bypass those assertions anyway.

This is confirmed by this post:

PreventUserIdleSystemSleep: per the docs, the system should still sleep if you close your laptop’s lid, or sleep manually.

The PreventUserIdleSystemSleep docs:

The system may still sleep for lid close, Apple menu, low battery, or other sleep reasons.

It looks like we’re hitting a rock wall here. No appropriate solution out there, my only suspects turned out to be innocent, and I still can’t reliably put my Mac to sleep from the Apple menu!

Digging deeper

We already tinkered with pmset earlier, and that’s what we’ll use to find more about the problem. We can use pmset -g assertionslog to show a log of the sleep assertions! Like pmset -g assertions, it’ll show the current assertions (whatever may be preventing sleep), but it will keep running and print any further event related to sleep (or not sleep)!

So I can run pmset -g assertionslog, then click the Sleep button from the Apple menu, and see what’s in the logs when the screens light back up right away.

$ pmset -g assertionslog
Showing assertion changes(Press Ctrl-T to log all currently held assertions):

Action      Age       Type                          Name
======      ========  ====                          ====
Created     00:00:00  InternalPreventSleep
Created     00:00:00  InteractivePushServiceTask
Released    00:00:24  PreventUserIdleSystemSleep    Powerd - Prevent sleep while display is on
Created     00:00:00  NoIdleSleepAssertion
Created     00:00:00  InteractivePushServiceTask
Released    00:00:00  InteractivePushServiceTask
Created     00:00:00  InteractivePushServiceTask
Created     00:00:00  InteractivePushServiceTask
Released    00:00:00  InteractivePushServiceTask
Released    00:00:00  NoIdleSleepAssertion
TurnedOn    00:00:00  UserIsActive         service:AppleMultitouchDevice product:Apple Internal Keyboard / Trackpad eventType:11
Created     00:00:00  InteractivePushServiceTask
Created     00:00:00  PreventUserIdleSystemSleep    Powerd - Prevent sleep while display is on
Created     00:00:00  NoIdleSleepAssertion

I highlighted the parts that were relevant in our case. First, we can see that when we explicitly sleep, powerd do release its “prevent sleep while display is on” assertion, so it effectively doesn’t prevent sleep anymore!

However we see just after that UserUsActive was turned on, by “tickling” the trackpad. What?

The moment it clicked 🤯

Then it occurred to me: when I click the Sleep button, my hand is, well, on the trackpad, and it stays there for a fraction of a second after I click. That’s a fraction of a second too long, because the mere fact of me removing my finger from the trackpad triggers an UserIsActive event which wakes the system right back up!

So the solution is simple: I need to remove my finger from the trackpad immediately after I click the Sleep button!

I couldn’t believe I spent hours to figure this out. I played around with it and it’s 100% that. The Sleep button actually works great, regardless whether or not I have an external display connected, as long as I don’t keep my finger on the damn trackpad for even a fraction of a second after clicking it. The gentlest touch will wake everything up right away, even if it happens half a second after clicking that button.

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