M4 Mac mini with macOS Tahoe 26.2 restarts every minute due to CPU overload

unplug all non-essential peripherals when testing

Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus

all known to cause issues on the macOS

To trouble shoot further you can:

—A SafeBoot Start up your Mac in safe mode - Apple Support will sort many anomalies

Does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, third party system modifications and system accelerations are disabled temporarily.

Login and test. Reboot as normal and test. Caches get rebuilt automatically.

This test will tell you if third party interference; most extensions etc are not loaded in safe boot mode.

—Test issue in another user (or guest user) account Change Users & Groups settings on Mac - Apple Support

This will tell you if it a universal issue or isolated to your user/admin account. 

*** (if you are using a wireless keyboard with rechargeable batteries— connect the charging cable, this will make the wired keyboard successful Safe Boot your Mac.)

Further—

You can get a good look at your User/System config. and reveal conflicts or issues, you can download/run this trusted utility https://etrecheck.com

If you need help interpreting the report you can post it here in its entirety in the "Additional Text" box in the editing toolbar below, in your reply.

If LeroyDouglas' suggestion doesn't fix your problem, then I suggest the following solution, which I have used to get my Mac mini M4 out of a similar problem:

TAKE YOUR TIME THROUGH THESE INSTRUCTIONS FOR A HAPPY RESULT! 😀

1. Go into System Settings and click on your Name at the top to get into your AppleID account on your Mac.
2. Click on iCloud
3. Under Saved to iCloud, click on See All
4. Provided you have enough iCloud storage, I recommend checking everything you want backed up, including: Keychain, Passwords, Contacts, Photos, Messages, iCloud Drive, etc.

IF you don't have enough iCloud space to backup the above, I highly recommend you get some additional iCloud space, even just temporarily for 1-month. iCloud makes it easy vs doing it manually with a backup device.

Once you have enough iCloud space:

1. Go into System Settings and click on your Name at the top to get into your AppleID account on your Mac.
2. Click on iCloud
3. Under iCloud+ (this may only appear after you've purchased some additional iCloud space), click on Manage...
4. Click on Other to see what else is marked to be backed up to iCloud
5. Be sure to Sync Photos and iCloud, too.

NOTE: While Apple recommends using TimeMachine to backup before proceeding, I don't recommend it at this point of your Mac recovery, as you do not want to backup and restore the problem software and/or corrupted files, which introduced your current problem.

Because of this risk, I deleted my TimeMachine backups once I was sure I had everything I wanted backed up safely in iCloud or iCloud Drive.

I wrote All of the above instructions and additional information to help you be sure you have all of your data safely stored away before wiping your drive and re-installing macOS Tahoe 26.2.

Here's Apple's official instructions on backing up your Mac::

How to back up your Mac

Lastly, with all your data, contacts, passwords, keychain, photos, etc., and all 3rd party app data safely backed up (data only, do NOT backup apps!), you should be ready for the complete wipe and re-install to make your Mac mini like new again.

How to reinstall macOS - Apple Support

I'm a musician and Logic Pro user and I can tell you that despite losing hours or even a day, wiping the drive and re-installing everything from scratch, it was well worth it.

In fact, it worked so good, that next time there's a major MacOS upgrade following Tahoe, I will very likely wipe my drive and install the new OS from scratch again. Tahoe works and feels better now that it did after upgrading from Sequoia.

John

johne154--

Although your heart is in the right place, ERASING your Mac without a Time Machine backup is a HUGE mistake. Don't EVER do that!

When choosing a Time Machine Backup drive, a drive two to three times the size of what needs to be stored is best for long-term, trouble-free operation. Making a backup of everything you want to save onto a drive that big is NOT risky -- it is exactly what you want to do.

-----

"On the cloud" is great for sharing photos, but is not a very good backup solution for everything you have. The stuff is not under your control, and is subject to sloppy handling, arbitrary changes in policy, theft, accidental deletion, data loss [are they making frequent backups using best practices?], and discontinuation or throttling of the service. It can easily take three days to restore it at ordinary Internet speeds. And that restore is unnecessarily complicated.

Also, it is premature to re-Install MacOS when the original Author has not yet responded with more information. There is not even a guess about what might be wrong.

In more recent versions of macOS, a re-install is rarely necessary (or sufficient to solve performance or crashing problems). Far more problems are solved by careful analysis, typically starting with (as leroydouglas suggests earlier) an Etrechck report.

Johne154 wrote:

If LeroyDouglas' suggestion doesn't fix your problem, then I suggest the following solution, which I have used to get my Mac mini M4 out of a similar problem:

TAKE YOUR TIME THROUGH THESE INSTRUCTIONS FOR A HAPPY RESULT! 😀1.

Go into System Settings and click on your Name at the top to get into your AppleID account on your Mac.

2. Click on iCloud

3. Under Saved to iCloud, click on See All

4. Provided you have enough iCloud storage, I recommend checking everything you want backed up, including: Keychain, Passwords, Contacts, Photos, Messages, iCloud Drive, etc.

5.

IF you don't have enough iCloud space to backup the above, I highly recommend you get some additional iCloud space, even just temporarily for 1-month. iCloud makes it easy vs doing it manually with a backup device.

...

In fact, it worked so good, that next time there's a major MacOS upgrade following Tahoe, I will very likely wipe my drive and install the new OS from scratch again. Tahoe works and feels better now that it did after upgrading from Sequoia.

John

I don't really agree with this approach:

• It does not address the root cause, which is likely something that has been installed that is incompatible with Tahoe.
• As Grant points out, more investigation is needed to understand what is causing the problems. In most cases, it is something installed that one uninstalled, fixes the issue; but sometimes it is hardware -- restarting every minute could certainly be caused by faulty hardware.
• iCloud is not a "backup" for Macs. It is a mirroring or synchronization tool between devices that are on the same iCloud account; it also can be used for primary storage "in the cloud" to save storage on the user's Mac. But it is NOT a backup. If a file is deleted from the Mac or from iCloud, it is deleted everywhere on all devices. With a true backup, one can delete the primary storage location and then restore from the backup. Grant also points out other shortcomings of treating iCloud storage as a "backup." [Note that for iPhones, one can create a true "backup" of the iPhone in iCloud, that is a separate service that is not offered for Macs. From the iPhone backup, one can restore an iPhone to be IDENTICAL to the originally backed up iPhone.] Also, iCloud stores only certain Mac folders and directories, it does not for instance mirror or synchronize all the contents of the user Library, which can contain substantial files and data, including for some users all their third party emails, among other things. So all that is "lost" if one erases one's computer with only what is iCloud preserved.
• The complete erasing of the Mac might not cure the problem if there is a problematic installation and the user simply restores their Mac to the way it was before.

This was exactly what guys here suggested to me and it fixed all my issues.

• "The complete erasing of the Mac might not cure the problem if there is a problematic installation and the user simply restores their Mac to the way it was before."

And what will do that? TimeMachine!!

It was guys here who pointed that advice out to me—do NOT restore from TimeMachine.

That was very sensible advice from all of you.

I know you think this is extreme, but to clear the problem in 1-day vs revisiting here and hashing over and over what could be going on, especially when his problem sounds so "severe?". Sounds like you think his problem can be solved easily, but in the meantime, he's still having a machine restarting over and over.

I'll step aside and wait to see what his solution ends up being and how long it takes to resolve.

John

<<. It was guys here who pointed that advice out to me—do NOT restore from TimeMachine. [it just} restores their Mac to the way it was before. >>

You need not restore EVERYTHING saved on a Time Machine backup. You can be much more selective in both What is restored and from When.

Time Machine saves, and can re-create, ANY Moment in time for which it still holds backup files.

Example: a user posted that they had installed software that messed up their files. it was installed mid last week. They had done an ordinary restore to recover, but that restored to yesterday, and the problem was still there. 

Readers were able to guide them to Time Machine.APP (not to be confused with Time machine preferences). This allowed them to look at the state of the major folder involved, back in time through each previous backup, until right BEFORE the bad software was added -- mid last week-- and restore as of that moment.

That worked great, and they were thrilled.

"The complete erasing of the Mac might not cure the problem if there is a problematic installation and the user simply restores their Mac to the way it was before."

And what will do that? TimeMachine!!

In reference to the quote you provided, no, it won't. The OS is mounted read-only from a sealed snapshot which cannot be altered. Time Machine cannot back it up and it cannot restore the old one.

Now, the third-party system modification you have installed are stored in the Data volume separate from the OS, so if you restore "everything" from Time Machine, you will restore the crapware causing your issues. Just migrate your data. Reinstall any apps you require. Don't reinstall the crapware.

But, you are correct, erasing the entire Mac is a complete waste of time. Erase all Contents and Settings may be prudent if you cannot find the offending software you installed at some point that most likely worked correctly under an older macOS.

Macs do NOT restart due to CPU overload. They simply slow down.

Also, the percentages shown in Activity monitor are percentage of ONE CPU, and you likely have about ten CPUs.