iMac keeps going into sleep mode every 10 seconds

Question

iMac keeps going into sleep mode every 10 seconds

Out of the blue my iMac keeps going into sleep mode every 10 seconds. I’ve tried everything. Rebooting, turning it off, … I even tried safe mode but it keeps going into sleep mode even during safe mode. There’s no time even to connect wifi or to use Time Machine to backup. I think it’s a coincidence that this happened when internet technician was at my place changing routers to fiber connection. Or is it not? Any comments? I’d appreciate any help you could give me. Thank you!

Posted on Jun 18, 2025 11:28 AM

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Answer 1

Allan Jones

Level 9

77,660 points

Jun 18, 2025 11:48 AM in response to eddiefromcuritiba

Please help us help you.

iMacs have been in continuous production since 1998 in five broad families with varying troubleshooting steps. We can more effectively help you in this setting if you provide your iMac sub-model and its mac OS version.

We are end users like you with no way to see or remotely access your computer. We can only work with details you provide. Details get you faster help and responses most appropriate to your situation.

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Answer 2

John Galt

Level 10

154,898 points

Jun 18, 2025 12:13 PM in response to eddiefromcuritiba

Ok, is that link not working for you?

For an Intel Mac, Reset the SMC of your Mac - Apple Support is applicable. If you are unable to open those links please write back and I will describe the instructions for your model Mac.

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Answer 3

John Galt

Level 10

154,898 points

Jun 24, 2025 11:06 AM in response to eddiefromcuritiba

Perhaps. Reset NVRAM according to Reset NVRAM on your Mac - Apple Support.

Please note those instructions are not applicable to any M series Mac.

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Answer 4

Old Toad

Level 10

215,130 points

Jun 28, 2025 4:34 PM in response to eddiefromcuritiba

If all else fails give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following;

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

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