How to fix my Mac mini heating up in sleep mode?

Early this morning, I noticed a similar issue with my new M4 Mac mini. Despite reaching out to support, the problem remains unresolved. They suggested disconnecting my two external drives (a 1TB SSD and a 2TB HDD), which undermines the purpose of using Time Machine for backups.

What’s puzzling is that the Mac mini stays cool during heavy usage with no fan noise, but after going into sleep mode for 20-60 minutes, it becomes very warm—almost excessively hot. With ample airflow and space around it, I would expect it to stay cooler while idle. I also ran Apple Diagnostics, but no issues were detected.

Any insights or similar experiences?

Not snapshots.

4 TB written in previous year.

1.2 TB written in 2 weeks.

"You can get the internet to agree with you on anything 😁 didn't you know that?"

Don't you realise the exact same can be said about here?

Then what’s the purpose for Apple to design this sleep function?

[Edited by Moderator]

I could speculate but it’s against the rules, unfortunately. How about this for an answer: don’t know, don’t care and neither should you..have a nice day!

I can’t put mine into sleep anyway it keeps waking up the monitor. I guess this is a blessing in disguise.

I'm having exactly the same problem. However, this issue seems to have started after I enabled the Apple Intelligence. I suspect the AI is doing some work in the background. During the "sleep" after display inactive period, my wired mouse light kept on, meaning the mini is actually NOT in sleep mode. After waking up, my M4 mini gets cool again. If I manually put the mini to sleep mode, it does turn off the mouse light, the fan stops, and the case remains cool.

“Prevent” should be checked - see @den.thed’s post. The bottom line is that it’s a result of faulty operation, not “bug”. If the settings are correct and the machine is not manually put to Sleep, no problem.

Apple makes no such recommendation or guidance re:sleep. Shutting down is your call depending on your preference - overnight shuts is mine. It doesn’t wear components compared to Sleeping. The power button placement has nothing whatsoever to do with this - I hardly ever use it even though the overnight shutting is daily - go figure.

If overnight shuts isn’t your cup of tea, you can leave it on with the settings as shown to disable Sleep and turn the monitor off. Good night!

You can get the internet to agree with you on anything 😁 didn't you know that?

You’ve left out important details in your reply, just extracting the sensational stuff and conveniently leaving out helpful suggestions from forum heavyweights on this so-called disk-write “problem”. At the minimum you should link to the thread so people can come to their own opinions.

Give it a break Ian! There’s got to be more to do with the new mini other than staring at the hidden power button, measuring oh-so-hot temps or snapping Activity Monitor every hour for precious aha moments.

Try Reddit or MacRumors if you want more traction, never fails…over here, not so much. All the best!

There is no silent killer and neither Activity Monitor nor unverified 3rd party DriveD are required to be continuously monitored for problems. Not even once a month. Be careful, if people keep leaping to conclusions based on snapshot numbers from Activity Monitor, I won't be surprised if Apple yanks the tool entirely or worse, starts billing $10 for every 10th occurrence :).

Bottom line: All Macs need is a little bit of TLC - not cranking up AM and DD every hour.

Also, excessive disk writes are a fact of external boot life - something Apple does not recommend but some choose anyway. It is dependent on hardware and software configuration which means it's different for every machine sold on the planet. The easiest way to avoid it is to boot internally like 99.99% of users do. Anything else is an invitation for trouble.

Anyway, glad you have found something that works for you. All the best!

So? Refer to your own discussion for what that could or could not mean (@Woodmeister) and my “FWIW” tip, and take it up there if you must. Bottom line: AM is conclusive of nothing when used standalone (hasn’t that been repeated a dozen times already).

My new mac mini m4 was still hot for 4 days while asleep, and then even after I adjusted all the settings that were suggested here....still, 102 F on the top of the case.....I turned off all wifi and the screen and it still stayed hot. Then I reached under it and shut it down for a few minutes...turned it back on and now everything is cool as it should be with wifi back on and doing other tasks.....I should have known this and rebooted it earlier....that's what you're always suppose to try first, right? Ha!

Came here because I noticed my m4 mini getting warm too. Turning off sleep is not an option, it should work without using that much energy that the mini gets warm.

I will connect an energy monitor tomorrow and see how much power it draws in sleep mode.

I've finally figured out a solution: set "Start Screen Save when inactive" to "Never" !

I used to have the exact same problem as you can see from my previous post. This setting change has put my M4 mini into proper sleep mode with wired mouse light turned off during the sleep mode. Please note, DO NOT turn on "Prevent automatic sleeping when the display is off". Otherwise, it will prevent your Mac going into sleep mode.

It seems this is a software bug which causes the Macs not going into the sleep mode if screen saver is activated and dynamic screen saver clips use a lot of energy (I can feel the case warming up quite quickly when running this type of screen savers).