Free space oscillating

[lordthistle]

I have a Macbook Air M1 with Mac OS 15.2 (24C101).

In the past two days the free space (on my 256GB disk) went from ~35GB to ~100GB then back again to ~35GB and back again to ~100GB (without any new installations/uninstallations, clearly).

Is there anyone who knows what's happening on this device?

I attach two screenshots taken within a few minutes.

 

[madams1000]

No one is in a better position to diagnose it than you. You have not provided even the most basic troubleshooting data necessary to further isolate the issue.

 

[DeltaMac]

Probably just some variation with some apps that create temp files, such as caches and the like, then delete those files when you close the spps. That seems like a large variation, but the most likely to me.

 

[lordthistle]

No one is in a better position to diagnose it than you. You have not provided even the most basic troubleshooting data necessary to further isolate the issue.

That’s because I do not know which info might help in diagnosing it. I have lived the past years with 30gb free and now, all of a sudden, I have 100gb available. I really do not know where to look at.

I have done several scans with daisydisk but cannot see where the space has been freed. My home folder, where I keep all my Cloud drives, remained of the same size.

 

[Sciuriware]

That’s because I do not know which info might help in diagnosing it. I have lived the past years with 30gb free and now, all of a sudden, I have 100gb available. I really do not know where to look at.

I have done several scans with daisydisk but cannot see where the space has been freed. My home folder, where I keep all my Cloud drives, remained of the same size.

You do not have control of the system partition: I found that installation kits and upgrade downloads there
come and go, without your consent. As it should be.
Do not worry too much and keep track of your own data.
A solution I made was a tiny task that lists my files in a text file and compares it to the real world from time to time.
As I write JAVA programs I added a checksum per file, but you do not really need that.
;JOOP!

 

[Sumo999]

macOS is notoriously ineffective at keeping track of free space. I've had variations as much as 500GB on my 2TB internal SSD. iCloud drive can also mess with these numbers.

 

[MacCheetah3]

Purgeable Storage Space on Mac: What it is & How to Free It

You may find a “Purgeable” storage space when looking at disk storage and disk usage in modern versions of macOS, including Big Sur, Catalina, Mojave, Sierra, etc, either within the Abo…

osxdaily.com

?

 

[Sumo999]

Counter-intuitively, "optimize mac storage" is the correct setting for allowing iCloud Drive files to be evicted locally

 

[PeterDinklageFan]

I have a Macbook Air M1 with Mac OS 15.2 (24C101).

In the past two days the free space (on my 256GB disk) went from ~35GB to ~100GB then back again to ~35GB and back again to ~100GB (without any new installations/uninstallations, clearly).

Is there anyone who knows what's happening on this device?

I attach two screenshots taken within a few minutes.

It's not just you! Since updating to 15.2 on multiple occasions I've seen my Mac report 220 GB of free space... on a 256 GB SSD with at least 90-100 GB of actual space used. It spontaneously corrects itself every now and then so I don't have a screenshot unfortunately, but even when viewing the disk space usage in Settings or Finder it's reported incorrectly. Funnily enough, the Applications folder is correctly reported as ~25 GB used in Settings while the space used is still reported as 19-20 GB. The "System Data" section also loads infinitely when this bug happens so it may be worth checking that out the next time this happens to you.

If you want the actual amount of disk space used, check Disk Utility. It's really annoying how unclear the macOS filesystem is when it comes to showing you how many storage you are actually using. It is one of the things Windows is simply better at doing.

I am almost certain this issue is an odd bug of some kind.