iMac M3 Peripherals waking up during sleep

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Level 1

16 points

iMac M3 Peripherals waking up during sleep

On an iMac M3 running Sequoia 15.2, I have an external hard drive for Time Machine, a Logitech G502 mouse with a light, a Stream Deck and a headset with lit volume controller. When the Mac is in Sleep mode, the peripherals wake periodically (lights come on) for no apparent reason and then turn off after a short time. This problem occurred on the my previous Intel iMac and in earlier versions of the MacOS. All four settings in System Settings/Energy are deselected. I have unmounted and disconnected the external hard drive to eliminate Time Machine as the issue. Clearly, something is waking the peripherals but not the Mac. Can this be prevented?

[Re-Titled by Moderator]

iMac 24″, macOS 15.2

Posted on Jan 16, 2025 9:34 AM

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Answer 1

TonyToronto Author

Level 1

16 points

Jan 17, 2025 9:03 AM in response to hcsitas

That strategy works, although the Stream Deck has its own sleep settings unaffected by Lock Screen. The headset is connected to a second display that slept intermittently when the iMac was sleeping but ignores Lock Screen even though the display sleeps, but turning it off turns the headset off. Thanks.

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Answer 2

hcsitas

Level 6

13,526 points

Jan 17, 2025 9:09 AM in response to TonyToronto

Great, thanks for updating. Not to be picky, but displays are turned off either by software or manually and computers sleep (if set to do so or manually). Technically this difference is important especially for troubleshooting issues.

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Answer 3

hcsitas

Level 6

13,526 points

Jan 17, 2025 9:38 AM in response to TonyToronto

Whether it’s Sleep or Display off on timer, the Mac sends a command to the display to turn off. The headset light is confirmation that the display unit still has power but has been commanded remotely to turn only display functionality off. That doesn’t mean the headset works - it gets its audio from HDMI which is blocked for all functions.

I of course don’t mean to correct you but take the opportunity to simply share my knowledge.

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Answer 4

hcsitas

Level 6

13,526 points

Jan 16, 2025 9:43 AM in response to TonyToronto

Sleep is unnecessary on later Macs and should be disabled. Shut for long absences/idle overnights, and for regular operation, use the settings exactly as shown below (reboot after setting):

Also, do not manual-sleep for brief absences, use instead the Lock Screen settings to switch the display off on timer:

Once set, you can also use Control-Command-Q to immediately lock your screen (instead of waiting for the display to switch off on timer).

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Answer 5

TonyToronto Author

Level 1

16 points

Jan 17, 2025 9:58 AM in response to hcsitas

All good. I’m grateful for a chance to learn something.

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Answer 6

TonyToronto Author

Level 1

16 points

Jan 17, 2025 9:25 AM in response to hcsitas

I guess that when the iMac was set to sleep, the second display lost its signal and entered its own sleep mode. Because the headset light “cycled” when this happened, I assumed the iMac was managing both. Not quite so, it seems, since the headset light remains on in Lock Screen. This is all detail. Lock Screen is an improvement on Sleep in my situation.

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