M4 Mac mini keeps freezing and restarting, even in safe mode

You might as well use the following, which would probably be exactly what the Apple Genius Bar would do before they would begin to diagnose this issue

If the user believes these current issues stem specifically from macOS 26 Tahoe.

For a thorough test of both Tahoe / Hardware and to  determine the root cause of all the computer issues.

Use the “Atomic” option and select “Erase All Content and Settings.” Apple Silicon computer

Use the Erase All Content and Settings feature to quickly and securely erase all settings, data, and apps, while maintaining the operating system currently installed.

Always make a Time Machine backup before proceeding.

Run the computer without installing any additional software and without restoring from your Time Machine backups.

Run the computer for approximately 1 to 2 hours

Report back if the previous issues reoccur.

Personally, my M4 Mac Mini with Tahoe 26.5.1 , 16 GB Unified RAM and 512 GB SSD drive just flys along

What peripherals do you have attached?

Open Activity Monitor after a reboot and select CPU monitor . Monitor for any process that is consuming a lot of CPU. If nothing seems excessive, do the same process for disk activity.

Are you using a Bluetooth keyboard and mouse? What may seem like a computer freeze may be loss of keyboard and mouse function. This could indicate a faulty Bluetooth chip or a lot of interference in the Bluetooth frequency band. Interference can be due to faulty attached device cabling.

There is also a possibility that you have installed some software or hardware driver that is not playing well with the OS.

Also, how large is your SSD and how much space are you using. If there is only a small amount of free disk space left, that can also cause severe issues.

+1 In addition to working thru the things that woodmeister50 has suggested.

Schedule an appointment at your local Apple Store or Apple Authorized Service Provider and have it looked at.

To find a local Service Provider, go to Find Locations and click on Explore Service Location.

Run the third party app EtreCheck and post the complete report here so we can examine it for possible clues.

How to use the Add Text Feature When Posting an EtreCheck Report - Apple Community

n68 wrote:

ok thank you: I have the same Mac mini configuration as you.

Nice to know, but what does that have to do with the issues you have described ?

Reinstalling Tahoe 26.5.1 on top of the existing installation of Tahoe 26.5.1

It will not. generally, change anything you have installed in the way of Third Party Software, configurations and settings

Having spoken to Apple Support several times and this have not gotten any better and then come here to the Forums and by virtue of posting your, you are asking Fellow User like yourself for Help

Help has been offered by at least 3 separate and experienced / knowledgeable users

Where do you what to go from there ?

HWTech wrote:

Run the third party app EtreCheck and post the complete report here so we can examine it for possible clues.

How to use the Add Text Feature When Posting an EtreCheck Report - Apple Community

This should be interesting as OP says " freezing and restarting, even in safe mode "

Maybe they will be lucky ?