MacBook Pro running hot with loud fans after forced migration to Tahoe

The current version of macOS Tahoe is 26.7.1. If you are running an older version, then the first step is to update your Mac to the current version.

See: Update macOS on Mac - Apple Support

Your Mac supports Tahoe (though not Golden Gate), and as such Tahoe should run fine on your Mac.

It is possible there are processes running in the background that are using significant resources. Check Activity Monitor, CPU tab (sort by % CPU) and Memory tab (sort by Memory) to see what's running hard.

Activity Monitor User Guide for Mac - Apple Support

If nothing in the above reveals an obvious culprit, then appropriate troubleshooting steps are Safe Mode and creating a new user account to test. 

See if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

Start up your Mac in safe mode - Apple Support

If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

Add a user or group on Mac - Apple Support

Once the testing is complete, the new account can easily be deleted.

Delete a user or group on Mac – Apple Support

If you have 3rd party ‘protection’ software installed, that may be the problem. That includes:

• Cleaners (software claiming to automatically free up space)
• Optimizers (software claiming to make your Mac run faster)
• Antivirus software
• VPN software (unless provided by a school/employer to enable access to internal resources from a remote location)

Such 3rd party system ‘helpers’, ‘cleaners’ and ‘protectors’ do more harm than good. In fact, such products are completely unnecessary for macOS and the only ‘good’ (if you want to call it that) they do is to put money in the developers’ pockets. Cleaners and protectors cause compatibility issues, often after macOS updates. Commercial VPNs claim to hide your browsing activity from websites, and while that may be true those VPN providers just sell your browsing data to others. For the user, all of these types of software offer only harm…and if that is limited to harm to your bank account, then count yourself lucky. If you have installed such software, follow the developer’s instructions to completely uninstall it (note that some developers fail to provide instructions and their software installs can be pervasive, meaning the only way to truly remove it is to erase your Mac, reinstall macOS then restore your user files from a backup).

It might help to download and run EtreCheck, written by a long-time forum member. The free version is fine. Post the full report using the Additional Text button. No personal information is revealed. 

If kernel_task is using a large percentage of your Mac CPU - Apple Support

Applications -> Utilities -> Activity Monitor -> View (menu) -> All Processes -> CPU (tab) -> Search -> kernel_task

At work, it was very common for older intel based Macs to accumulate dust/smoke particles/pollen in the fan and on the cooling surfaces.

Those users would take the Mac to an Apple Store or service center and have the dust cleaned out. Afterwards, the Mac ran much cooler, the kernel_task was no longer using hundreds of percent CPU.

Have you tried booting your Mini into Safe Mode? This often clears glitches such as yours.

Start up your Mac in safe mode - Apple Support

Follow the instructions for Intel based Macs.

chris.radford wrote:

I suspect something is broken in Tahoe

If that’s the case then why are you the only one reporting this issue? Critical thinking would indicate that if this is some kind of bug in Tahoe there should be thousands of reports. There are not. In addition Tahoe has reached its most stable point in its lifespan.

You are not communicating with Apple in these user forums. No one here is an Apple employee or contractor. Apple Support neither participates on nor monitors these user-to-user forums except for moderation. You may submit feedback to Apple using the link provided.

Feedback - macOS - Apple

Going forward though, Tahoe will not likely receive any more updates except for security and privacy patches. macOS 27 Golden Gate is now front and center.

As for switching away from Apple you should always do what’s best for you. We fellow users don't really care what you do. Threats like yours fall on deaf ears.

It's entirely possible that your aging intel based Mac is just plain old and developing problems with thermal regulation.

In what way was the "migration" to Tahoe "forced"? And what, exactly, do you mean by "migration"?

Do you mean upgrade? Migration from another Mac? Something else?

PS: I don't have the same problems when running Windows on this machine. It runs like a dream. This is a Tahoe-specific issue.