MB Air M4: permanently calculating storage items

Reducing System/Volume/Data is a 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

How to free up ‘System Data’ and other storage on your Mac from a fellow colleague  @ neuroanatomist

Use another application to see where space is being used  Storeograph  on the Apple Apps Store 

View APFS snapshots in Disk Utility on Mac - Apple Support (CA)

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

Understanding iCloud Drive from a well written User Tip from @ Richard.Taylor

There are  two effective ways to remedy this issue:

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, such as 256

The 256 GB Drive Capacity in 2025 is akin to when Apple sold computers with 128 GB Drive Capacity

For example, the 13-inch MacBook Pro around 2017 offered a 128 GB storage option, and Apple sold these configurations into 2018.

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.

That "calculating" issue is not an uncommon occurrence. Plus even when working is not quite reliable in terms of dis usage by category. Sometimes a complete wipe and reinstall can solve it but really isn't worth the effort.

If you want to track storage usage, there are fere and paid app alternatives and can be much more informative as to disk usage.

Two free apps are Omni Disk Sweeper and Grand Perspective. The first is a pretty basic list type of application listing usage in a hierarchical manor. I personally use this app occasionally to track down data hogs and basic "housecleaning". Grand Perspective does the same thing but does it with pretty pictures.

A paid app that I have looked at and seems pretty good is Daisy Disk. This, like Grand Perspective is graphical but is a bit more polished (as it should be for a paid app).

Note that none of these apps do any automatic removal of anything like some "cleaning" apps which can often remove things that should not be removed.

willywonty wrote:

My wife's M4 MB Air (250 GB storage, latest Tahoe OS) has an odd problem: two of the storage items (Photos and System Data) are permanently showing "calculating" instead of a value. In an attempt to cure the issue, I updated her Air from Sequoia and deleted all the photos and loads of documents, but no joy. The storage item values are as follows: Applications 22 GB, Documents 10 GB, Mail 16 GB, MacOS 23 GB, Photos [calculating], System Data [calculating] (the amount of storage being calculated is shown as 129 GB!), Available 43 GB.

By my reckoning, most of the storage being calculated should be shown as being available, since there are no photos present in storage.

Any ideas?

I have to agree with Woodmeister about DaisyDisk. I purchased a license to DaisyDisk (which allows it to be used on more than one Mac). When run as Administrator, it will show you where ALL your disk space is being utilized. This makes it very easy to identify where one can reduce to free up space.

As for "System Data" and "Calculating," that Storage tool is no longer very useful on Macs. I have several Macs and some show all the categories filled in (how much storage), others show "Calculating" in one or more categories. I don't think there has been any clarity found online in what causes "calculating" to never end for some Macs in some categories. That said, the "System Data" category includes some actual system-related files but also includes many user controlled files that for reasons unclear have not been sorted into the appropriate category. This can include some Mail files/attachments as well as Photos libraries that are not designated as the Photos System Library. As well as other files such as maps and support files downloaded for Garmin (or similar) devices and many other things. Because it is a melange of types of files, it is not a useful metric for the user trying to save on storage.

As provided by Owl-53, this link may be helpful How to free up ‘System Data’ and other storage on your Mac but you still can't get around the fact that many user/application files might be included in "System Data."

I suggest DaisyDisk (not free, but not very expensive either) as the best way to get insight into your disk usage and guidance to reduce it. DaisyDisk is not the only such utility, I have used several, and others do work well but I have found DaisyDisk to be the easiest and clearest with a friendly user interface.

willywonty wrote:

Thanks to all for your responses. Rebuilding the Spotlight index has made no change to the "calculating" issue (System Data and Photos). The point is that my wife's Air has relatively data in storage (see my OP message), but a massive 130 GB or so of disk space being calculated and thus not available. My own M4 Air, bought at the same time, shows all the storage values correctly. My System Data value is 35 GB, so I would expect hers to be about the same – and zero for Photos, as she has none. In other words, she should have around 90 GB more available storage than is being shown.

I will pluck up courage to erase her HD and start again!

Yes, what you have said many solve the immediate issue

Though, unless one take the time and makes the effort to explore this issue in greater detail

The issue of Storage may return

willywonty wrote:

My wife's M4 MB Air (250 GB storage, latest Tahoe OS) has an odd problem

No, it's a normal problem. The hard drive is too small.

In an attempt to cure the issue, I updated her Air from Sequoia

Updating will not cure any issues. It only creates new issues.

The storage item values are as follows: Applications 22 GB, Documents 10 GB, Mail 16 GB, MacOS 23 GB, Photos [calculating], System Data [calculating] (the amount of storage being calculated is shown as 129 GB!), Available 43 GB.

Disregard all of that. Apple's "Storage" display has been notorious for being wrong for many years. The less free storage you have, the worse it will be.

By my reckoning, most of the storage being calculated should be shown as being available, since there are no photos present in storage.

Any ideas?

As I said, the hard drive is too small. The ideal solution would have been to post your question a week earlier. Then you could have fixed it with a new MB Air with at least 1 TB of storage.

The point is that my wife's Air has relatively data in storage (see my OP message), but a massive 130 GB or so of disk space being calculated and thus not available. My own M4 Air, bought at the same time, shows all the storage values correctly.

Let me guess - your hard drive is bigger?

I will pluck up courage to erase her HD and start again!

That will fix the immediate problem. You'll get values from that Storage display, at least for now. But it doesn't really matter because those values are typically bogus. The problem is that this is a 250 GB drive. There just isn't that much storage available to work with. Apple software eats GBs like candy. Ideally, a Mac should have about 100 GB free. Any less than that and you'll start to experience performance problems and the kinds of "Storage" problems that you describe.

You'll have to be more aggressive about deleting files on that computer. To make matters worse, you can't actually delete files. You can only flag them for deletion by the system "deleted" daemon. Then, after a couple of days, the operating system will finally delete the file.

https://discussions.apple.com/thread/256216723

The sizes shown are based on Spotlight. You might want to rebuild your index.

Rebuild the Spotlight index on your Mac - Apple Support