Mac free space differs in System Settings and Finder

FYI, t absolute minimum is ~20-25 GB free space, and as a rule of thumb you should aim to have 15-20% of your total internal storage as free space. Terminology is important here – free space is not the same thing as available space. The one that matters is Free space, but what macOS shows in most places is Available space. Available space includes both free space and ‘purgeable’ space, the latter comprises system caches, snapshots and other data that macOS can delete if it decides more free space is needed. However, there is no way the user can force those data to be purged.

The place to check how much Free space you have is in Disk Utility (in Applications > Utilities), by selecting the main container disk below the drive itself (you may need to select View menu > Show all devices to see it). For example, on my M4 MacBook Pro, the Storage settings pane and Get Info on the internal drive show 1.24 TB of Available space, whereas Disk Utility shows there is 1.15 TB of actual Free space, 90 GB less than ‘available’. Although 90 GB is a small fraction of my 2 TB internal storage, that would not be the case with 256 GB or 512 GB of internal storage.

Note that you can also see the Free space in the System Report (System Settings > General > About > System Report button, at the bottom > Storage). 

Some steps to take to safely free up space:

Free up storage space on Mac - Apple Support

Optimize storage space on your Mac - Apple Support

How to free up ‘System Data’ and other st… - Apple Community

The difference between the free-space figures shown by Finder and System Settings does not necessarily mean that 60–66 GB of storage has actually been used.

It shows that macOS is currently reporting different storage figures.

The fact that System Settings also remains unable to finish calculating “Photos” and “System Data” is relevant because its Storage analysis is not completing. 

Apple describes System Data as a general category containing Apple and third-party files that do not fit into another category. (Apple Support)

The next step is to open Disk Utility, choose View > Show All Devices, and examine the internal physical disk, its APFS container, and the Macintosh HD volumes. 

APFS shares available space between volumes within a container, so the container-level information is useful when investigating the discrepancy. (Apple Support)

It is also important to distinguish free space from available space. 

Apple explains that available space can include purgeable space that macOS can reclaim when needed.

Consequently, the figures reported by different macOS interfaces do not necessarily represent exactly the same calculation. (Apple Support)

For now, I would not delete System Data, caches, or other files simply because the Storage calculation has not completed. 

First compare the figures shown by Finder, System Settings > General > Storage > All Volumes, and Disk Utility, making sure you note which volume or container each figure refers to. 

Apple specifically provides the All Volumes view for examining storage across the internal volumes and containers. (Apple Support)

If you provide the Capacity, Used, Available, and, where shown, Purgeable figures from Disk Utility, together with the figures shown by Finder and System Settings, the discrepancy can be investigated more precisely.

Apple's relevant documentation:

Free up storage space on Mac

See used and available storage space on your Mac

Get detailed information about a disk in Disk Utility

Add, delete, or erase APFS volumes in Disk Utility

Macs are infamously fuzzy on defining and reporting free disc space. The best place to look is in the Disc Utility App. Check the Data partition. The purgeable space is also, effectively, free space. It's just temporarily occupied until the Mac gets round to some HD admin but is immediately useable if the Mac needs it. Don't worry about the size of the AFPS snapshots - it represents the size of the files which were snapped, not the actual disc space occupied.

pazzi314 wrote:

About 15 minutes after this my previous reply (and right before my eyes) Finder jumped down to 200.64GB available. This still lines up with what Disk Utility is displaying (200.64 GB available).

Data now shows 281.7GB available with 81.06GB of those purgeable.

Curiously the file sizes of the APFS Snapshots also changed. While the smaller ones remained at 5.75GB and 25.17GB the largest one now sits at 52.33GB, which I find kind of confusing, since it is dated to 2026-09-13 and I would expect a snapshot to stay the same size.

Zurarczurx excels at understatement.

Much of what the system it telling you about storage is simply false. There's no other way to put it. In some cases, there are better sources of information. But until you get to a very low level of detail, down to storage blocks, below files, accurate information simply isn't possible.

First of all, ignore anything that says "available". That's a total fantasy. Don't try to do math with "purgeable" values either. What is "purgeable" anyway? It's actually used storage. And does it ever get "purged"? Not in the way you think, or on any kind of useful timeline.

For snapshots, the sizes it tells you are meaningless. There is a more accurate snapshot size, but you have to customize the snapshot table columns in order to see it. I think it's the "private size".

Even Disk Utility needs to be customized to "show all devices" before it will tell you the actual amount of "free" storage.

For ease of communication, I changed my system language to English.

My system is currently reporting the following sizes:

• Finder shows 280.48GB available.
• System Settings show 264.68GB available (while still being stuck calculating on Photos and System Data)

Disk Utility shows the following hierarchy:

APPLE SSD Media at 500.28GB

Container disk3 at 494.38GB (Free 201.72GB, Used 292.66GB)

Macintosh HD volumes at 494.38GB (Available 201.73GB, Used 279.98GB)

Macintosh HD (which is slightly grayed)

Macintosh HD snapshot

Data

To my eyes it seems, that the discrepancy between Finder and Disk Utility (at this moment) stems from the purgeable space.

I also turned on APFS snapshots and the purgeable portion mostly lines up with three local snapshots at 5.75GB, 25.17GB and 50.73GB

About 15 minutes after this my previous reply (and right before my eyes) Finder jumped down to 200.64GB available. This still lines up with what Disk Utility is displaying (200.64 GB available).

Data now shows 281.7GB available with 81.06GB of those purgeable.

Curiously the file sizes of the APFS Snapshots also changed. While the smaller ones remained at 5.75GB and 25.17GB the largest one now sits at 52.33GB, which I find kind of confusing, since it is dated to 2026-09-13 and I would expect a snapshot to stay the same size.