How to find what app is preventing screensaver from starting (Sonoma)?

Question

Since a couple of days I have been noticing that the screensaver was not kicking in at the specified interval (2 minutes).

I diplomatically assume it is not an Apple app, and currently I have Timemator, Sibelius, InDesign, Illustrator, Acrobat DC running as 3rd-party apps on top of macOS Sonoma 14.5 — M3 Max MacBook Pro.

An excellent post here discusses how to troubleshoot a Mac that won’t sleep. I’m looking to do the same on what prevents the Mac from being seen as idle and activating the screensaver before sleep happens.

Here is the result of the pm -g assertion thing in Terminal:

   Assertion status system-wide:
   BackgroundTask                 0
   ApplePushServiceTask           0
   UserIsActive                   1
   PreventUserIdleDisplaySleep    1
   PreventSystemSleep             0
   ExternalMedia                  0
   PreventUserIdleSystemSleep     1
   NetworkClientActive            0
Listed by owning process:
   pid 312(powerd): [0x00064dd800019f62] 00:47:39 PreventUserIdleSystemSleep named: "Powerd - Prevent sleep while display is on"  
   pid 77745(CEPHtmlEngine): [0x00063f4800059bf6] 02:19:20 NoDisplaySleepAssertion named: "Video Wake Lock"  
   pid 366(WindowServer): [0x000657d70009a4a5] 00:00:00 UserIsActive named: "com.apple.iohideventsystem.queue.tickle serviceID:1003119f0 service:AppleHIDKeyboardEventDriverV2 product:Magic Keyboard with Numeric Keypad eventType:3"  
    Timeout will fire in 300 secs Action=TimeoutActionRelease
   pid 359(bluetoothd): [0x000658ca0001a507] 00:00:57 PreventUserIdleSystemSleep named: "com.apple.BTStack"  
   pid 397(coreaudiod): [0x00064dd8000181a9] 00:47:39 PreventUserIdleSystemSleep named: "com.apple.audio.AVVCAggregateDevice-63958-16807.context.preventuseridlesleep"  
    Created for PID: 63958. 
    Resources: audio-in audio-out BuiltInSpeakerDevice 
   pid 397(coreaudiod): [0x00064dd800019b02] 00:47:39 PreventUserIdleSystemSleep named: "com.apple.audio.BuiltInSpeakerDevice.context.preventuseridlesleep"  
    Created for PID: 77190. 
    Resources: audio-out BuiltInSpeakerDevice 
   pid 63922(sharingd): [0x000657d70001a4a7] 00:05:01 PreventUserIdleSystemSleep named: "Handoff"  
Kernel Assertions: 0x8=BT-HID
   id=1494  level=255 0x8=BT-HID creat=23.07.2024, 07:20 description=com.apple.driver.IOBluetoothHIDDriver owner=AppleHSBluetoothDevice
   id=1495  level=255 0x8=BT-HID creat=23.07.2024, 07:27 description=com.apple.driver.IOBluetoothHIDDriver owner=AppleHSBluetoothDevice  

I believe Sibelius is preventing sleep, but it has never prevented the screensaver from starting in the past.

I thought the screensaver blocker was Adobe Illustrator but today, Monday morning, freshly boot up Mac after more than 24h off, it happened again, and Illustrator was not running, but Sibelius was.

I have found that the ScreenTime widget on the Desktop sometimes returns odd data which doesn't correspond to the reality of things. Clicking on it to open System Settings, and then Activity Monitor to make things sync seem to help, though I am not 100% this is the solution.

Once more, this has nothing to do with my Mac not going to sleep, but I need to understand how to allow my screen saver to engage when I am not using it for 2 minutes.

Is there a way short of shutting down each app and waiting for the screensaver to start to narrow down what’s happening here?

Answer 1

You are correct that most questions on power assertions here relate to sleep and not the screen saver. You can use those answers to get started, but focus on the UserIsActive assertions and text.

Here is a way to cut through the noise:

pmset -g assertions | grep UserIsActive

Your item is currently product:Magic Keyboard with Numeric Keypad eventType:3.

You should be able to test this quickly by disconnecting it and waiting the two minutes. If you are very curious you can also watch the log as you wait the 2 minutes:

pmset -g assertionslog

I would change all your sleep settings a bit if you don't see the UI matching what you have.

Maybe make sleep never or an hour - add a minute or 5 to the password and display off setting and bump the inactive up or down 1 minute and retest.

Answer 2

After several attempts at understanding what was going on, an update from the App Store came to the rescue. Following an update to the GoodNotes app, I noticed that, about 4 hours after the update—and without the app ever running—the ScreenTime widget on the desktop showed 3h43m usage of GoodNotes.
Finding it suspicious, I launched Activity Monitor and typed "Goodnotes" in the search field. Indeed, the GoodNotes process was there and, while it consumed little energy of memory, it somehow prevented macOS Screensaver from starting.
Upon terminating the process and waiting for the set time to elapse, the screensaver started normally. No macOS restart was needed. I have now uninstalled the GoodNotes app from my Mac. While I love the app on my iPad, its macOS counterpart is a far cry.
I hope this helps others and encourages them to use ScreenTime to find lingering processes that should just not be there.