Update to Sequoia 15.3 increases free space

I have just been on with apple Support and they have said

"Generally, we suggest the customers to update the device to improve the device performance and it will delete Cache/cookies and other unwanted files in case if it wasn't cleared regularly. 

That is the reason, it has been freed up the space on Mac. No need to worry, since device has all the files. It is expected behaviour"

They also said it is not a glitch

Parneix wrote:

Mac mini M1 2020, which I updated to Sequoia 15.3. Onboard SSD is 250 GB. Been running low on space for months. Checked prior to update to make sure there was enough space for the update: about 12.5 GB left.

Ran the update: was succesfull, no issue whatsoever. Disabled Apple Intelligence (never use it). And then noticed that my SSD now shows 118.5 GB of free and purgebable space. That’s quite a jump.

Maybe the various cloud storage solutions I’m using have kept most synced files online, but that would be a totally new behavior based on previous updates (OneDrive, Dropbox, pCloud, iCloud)

Don’t have a recent snapshot of my storage from 15.2, so comparison is not easy. So far, do not seem to have lost any files.

Wondering if anyone else experienced something similar. Thank you.

Does not sound like an issue.

I suspect Local Snapshots got cleared ref; About Time Machine local snapshots

Hello, I'd like to tell you what has been happening with my system ever since the 15.3 update. It's similar to yours, but more alarming.

The day the update came out, I checked my storage after seeing reports of Apple Intelligence taking up a few extra gigabytes of space. I was using 167 out of 494GB. Once the update was done, It said it was using about 20GB less space. Very strange, but I didn't think much of it. I went to the settings and turned off Apple Intelligence. The usage dropped another few gigabytes, but then I noticed something very odd: The amount purgeable was the same as the amount used. After a couple of hours, programs started having errors and then I noticed my files were being corrupted. I checked my storage again and it was down to less than 100GB used and storage overview software (TrashMe 3 in my case) confirmed that a huge amount of data was gone. Restarting only made things worse.

I finally decided to completely wipe my internal drive and restore a recent Time Machine backup. That worked for a few minutes, but then the storage started calculating wrong again and the same thing happened.

I wiped the system again and didn't restore from Time Machine. I manually redownloaded all of my programs, activated them, configured macOS to roughly how it was. All seemed fine... until I started redownloading Steam games. It got to about 80GB downloaded when the storage information in Settings messed up again. It doesn't seem to be deleting files this time and isn't reporting any space as purgeable, but it's clearly wrong. It says I'm currently using 19.66GB when the application size being reported is 25.16 alone. System Data is continuously calculating. First Aid through the Disk Utility doesn't work on either a volume level or partition level. Everything comes back as normal. This has to be a bug in the 15.3 update.

I will reply again if files start disappearing again.

Edit: I forgot to say I'm on a 2021 M1 Pro MacBook Pro.

Same - but larger increase.

MacBook Air M2 24/256

was at c.85GB free before update, now at 140GB free post-update

I keep my SSD below 75% for files as I do a lot of photo editing (incl panos that can be 1GB) so the increase in storage is most welcome - but I also doubt I had 55GB of crud on my MB Air. I clear caches, restart regularly and keep an eye on the system, so I could believe some crud but not 55GB...

all very strange but welcome nonetheless!

One important point that some people do not know is that you should NEVER fill up your drives.

There should always be at least 10% free or you are asking for real trouble.

Ideally you should never fill it more than 80%.

Drives need plenty of elbow room to work efficiently.

Filling the drive will cause it to fail prematurely as there is no spare space to even out the wear on the flash memory blocks.

I never let my boot drive get more than 50% full.

External SSDs and HDDs are now comparatively cheap and will help prevent excessive wear and damage to the vital internal drive.

Once that fails your computer is an expensive door-stop.