MacBook Air M1 storage discrepancy: Macintosh HD vs folders

Sorry. I was unclear in my previous post.

Time Machine snapshots are created on the startup drive if you have enabled Time Machine to back up automatically and don't always keep the backup drive connected.

MacOS does keep a number of Time Machine snapshots on the drive as part of the backup process.  TM snapshots can occupy a significant amount of drive space. You can disable the creation of these many TM snapshots by setting TM to backup manually rather than automatically at intervals.

You can view and manage these in Disk Utility or in the Terminal app.

View APFS Snapshots in Disk Utility on Mac - Apple Support 

livin1965 wrote:

Using a MacBook Air M1 with 256GB storage.

The amount of space that Macintosh HD says is being used is 212GB.

But, the amount of space that Finder lists as being taken up by the four folders (Applications, Library, System, Users) only totals 150GB.

......

Note that these are the only items that the user has direct access to via Finder. There is more that can only be found if one were to use Terminal. In addition, there is the sealed system volume that only the machine has access to at boot time which can be around 12GB or so (in Tahoe) which gets copied to a usable system. There is also around another 10GB or so on the disk for recovery and other OS only use.

You can see these if you use Terminal with the command:

diskutil list

Open up Disk Utility and look for Time Machine backups.

Reducing System/Volume/Data is a very common question. 

1 -  System data taking too much in MacOS Sono… - Apple Community

2 - Time Machine Local Snapshot won't delete - Apple Community

3 - Over 60% storage blocked by System Data - Apple Community

4 - Running out of storage - system data is huge after upgrade to macOS Tahoe 26.2

Suggest getting an External SSD Drive and start moving your Pictures, Videos, Music and any other large files you have control over, OFF the Internal drive and Onto the External

1. Quick Fix Actions:

For Apple Silicon computers, use Disk Utility to erase a Mac.

For Apple Intel computers, use Disk Utility to erase an Intel-based Mac, then reinstall macOS.

Always make a Time Machine backup before proceeding.

Migrate only the user account, not the entire system.

 Reinstall only the necessary applications from the Apple App Store or directly from the developers.

2 - Generally

When the user discovers this issue, it’s likely because the computer’s internal drive capacity is small 256 GB

Unfortunately, the user’s storage needs may have increased since the computer was purchased.

To future-proof the computer, consider spending extra money upfront on a larger drive capacity and adding more unified RAM.

Note - On Apple Silicon and newer computers. The SSD Drive and the Unified RAM are Soldered to the Logicboard and can not be upgraded.

You're welcome.

Thanks for the update. Happy to know you may have this sorted.

You might check my last post where I linked to info regarding APFS snapshots (a.k.a TM local snapshots) not TM backups as I originally posted.

Also, be aware that because you have only 256 GB of storage you must be mindful of how much data you allow to accumulate on this MBA. If your storage becomes too full the Mac may eventually refuse to boot, then it becomes very difficult - not impossible, tho - to recover. Aim for a minimum of 30 GB free, always, and 50 GB would be better.

🍀

To get a more complete view of the Drive Structure on Apple Silicon Computers

Yes, the article does reference macOS 12 Monterey

Though the Structure of the Drive remains unchanged

macOS 12 Boot Disk Structure (M1 internal)

As mentioned by my colleague @ D-I. Johnson

256 GB SSD Drive in 2026 could be the equivalent to when Apple Sold the Hugh 128 GB Drives for the Entry Level / off the self configurations