How to fix my Mac mini heating up 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).

MateuszStepien wrote:

Thank you for your reply. There is no other option for it to be in sleep mode though and not heat up?

You're welcome.

Is "Wake for network access" in the Energy Settings turned On...?

If it is, turn it Off and test.

Then if that doesn't help..?

Leave the Mac mini On with the Display(s) Off and Shut Down for longer periods of non-use.

How hot is it getting?

Is it just warm to the touch or hot?

What are the temperatures of the components? To find out, download the free MacsFanControl.

MacsFanControl

You can then see whether anything is getting too hot.

It is quite likely that the SSD is getting warm because during sleep the fan will not be operating. Once you wake up the fan kicks in at a slow speed and cools the machine down.

I cannot prove that theory but it seems plausible.

Spoke too soon: After going into sleep for 15min, my mouse lit up again, the mini fan started spinning again, the case got warm again. The mini just won't stay in sleep mode for long. After reading online about this issue, it appears this is a very common problem. The fix is to turn on "Low Power Mode" in Energy setting, and set all others to off including "Wake for network access".

The bottom line is that it's bug, albeit a low priority one.

Ian R. Brown wrote:

How hot is it getting?

Is it just warm to the touch or hot?

Those are excellent questions Ian.

What are the temperatures of the components? To find out, download the free MacsFanControl.

MacsFanControl

You can then see whether anything is getting too hot.

That observation will have to happen quickly after wake from sleep, because the fan would come on when you went to check the temp's.

It is quite likely that the SSD is getting warm because during sleep the fan will not be operating. Once you wake up the fan kicks in at a slow speed and cools the machine down.

I was thinking the power supply, the network card to allow wake for access and who knows what other components are drawing power in computer sleep mode.

I cannot prove that theory but it seems plausible.

Agreed.

Three days ago I discovered my M2 mini running Sequoia 15.1 was writing excessively to disk.

It had written about 4 months of data (1.2 TB) in a fortnight!

An internet search revealed it to be quite common and causing dangerous wear especially to small or cheap SSDs.

There is no sign of this excessive writing, nothing appears on your drive nor is there any impact on performance.

It might be worth checking in Activity Monitor to see whether your Mac is affected as it could be causing the heat during sleep.

It's a Spotlight bug which has been there since Ventura and Sonoma. Apple must definitely be aware of it, because it has been written about many times both here and on Reddit. I myself have this bug on my production Mac with two external SSDs connected. I disabled Spotlight via terminal, after first disabling System Integrity Protection. The writing stopped. It's a bug.

[Edited by Moderator]

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!

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes.

Then leave the Mac mini On with the display Off and only shut down for long periods of non-use.

Turn off "Low Power Mode"

Turn on "Prevent automatically sleeping when the display is off"

Then test for a couple of days.

To reach out directly to Apple, please send Feedback and contact Apple Support.

Feedback - Mac mini - Apple

Official Apple Support

Sleep is unnecessary on later Macs and should be disabled. Shut for long absences/idle overnights i.e and for regular operation, use the settings exactly as shown by @den.thed. Important: do not manual-sleep: leave on or shut down.

“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!

It is a fact that my mds_stores were writing excessively to disk and many other people have been reporting this since July.

The OP has not found a solution to his problem so I suggested this as something worthy of consideration as he has probably not read my thread.

The whole danger with what I suggested is that it is a silent killer . . . there is no sign anything is amiss unless you run DriveDX or watch Activity Monitor which most Mac users do not do.

I have disabled Spotlight search as shown below and now the writes are down to a normal level.

I had the same issue with my M4 Mac Mini (512GB): it would get hot when not being used, but it would be cool when actively being used. I tried many recommendations in this thread and tested them out, including a factory reset, but the issue continued to happen. The one thing I did not try was disabling spotlight search, but I use Spotlight very frequently, so that wouldn’t really work as a solution for me.

I called Apple Support and they recommended to bring it in to a store for a diagnostic. I did that, they kept it for 3 days, then concluded the hardware was fine and recommended another factory reset.

In the end I decided to return the Mac Mini and go back to my 14” M1 MacBook Pro, which still runs perfectly. Bummer, as I really liked the form factor of the Mini and was excited to have a dedicated desktop computer for the Studio Display. However, I had concerns for the longevity of the device with this issue going on, so the return option was the best choice for me. Hopefully this issue can be acknowledged and fixed in the future.