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>> Use Disk Utility to erase a Mac with Apple silicon. << Apple Silicon computers

For Intel computer >> Use Disk Utility to erase an Intel-based Mac followed by How to reinstall macOS

6a6b72 wrote:

That is obviously the last thing to try since I want to keep some data which I can’t backup now

Yes I agree with that statement

Though a couple of points to add

Point 1

What is done is done and that can not be changed but mitigated for the future

If you had used Time Machine Backup Utility  you maybe able to Restore the Deleted Files 

For future purposes

To truly protect your non replaceable Data - have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive 

https://bombich.com

With that in mind, the computer would not be vulnerable to having to Salvage the data at this juncture in time

Point 2

The final word from Apple on Managing the " System Data “ Category

System Data: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. 

You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.

There are areas of the Operating System which we users have control over and that is the User Account Folder ( Home Folder )

All other areas are not accessible 

It is generally a good computer practice to alway keep at least 20% to 25% of the Total Drive Capacity’s as Empty Space. Allowing the computer to drop below these guidelines may eventually, cause unintended consequences.

In this computers case 25.6 GB to 32 GB of Empty Space

The Operating System on Sonoma user byline " MacBook Air 13″, macOS 14.6 is between 9 GB or a little more

So between the Operating System and the empty Space suggestion mean 34GB GB to 41 GB of Space is used from the Get Go

Leaving 94 GB to 87 GB for the user to manage

There is no silver bullet but to be prudent on what is important and kept on the drive and what is not

I do really hope 🤞the suggestions from @BDAqua work out for this machine

But be prepared, the Nuclear Option may or may not be the only option

Start with this if M1, M2, or M3 Mac...

On your Mac, choose Apple menu  > Shut Down.

Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.

Press and hold the power button on your Mac until “Loading startup options” appears.

Select a volume.

Press and hold the Shift key, then click Continue in Safe Mode.

The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

Does the problem occur in Safe Mode? 

Restart normally.



Start with this if IntelMac...

Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode? Could take 10 minutes or more.

Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.

6a6b72 wrote:

1. Ok, I managed to crate a TM backup in safe mode. Since I have never on my 16 Mac user experience used TM, I have few questions:

Is it ok to use backup made in safe mode?

A - Yes

2. Do I need to create separate backups for each user if I have two on my Mac or a backup made by one user will recover both?

A - I would make Separate TM Backups, each to separate Dedicated External Drives

3. Will the backup recover only personal data and no system errors will be recovered?

A - TM Backup starting in about macOS 11 Big Sur and above Only Backs Up the User Account ( Home Folder ) It Does Not backup the Operating System

4. How and on what stage do I use TM recovery after I erase MacBook drive and install Mac OS anew?

A - Migrate ONLY the User Account(s) and nothing more