What to do with the system data problem?

Pål B wrote:

You don't have this issue on Linux though it have similar features. Caches, log files, temp files, config files, and all that is fine. I'm wondering why it can become so big on Mac OS. Is it system snapshots that can be removed ( I don't use Time Machine)? Siri, that I don't use?

macOS is not Linux. Comparing apples to ball bearings is only moderately useful.

Pål B wrote:

Just wanted to understand it. Perhaps it's normal and no mystery.

And that's exactly what you've been told. It can be perfectly normal and a mystery. What it is not is deception.

The last 5.25 Floppy I saw was for the then IBM Custom Operating System for IBM AS/400 line

Owl-53 wrote:

The last 5.25 Floppy I saw was for the then IBM Custom Operating System for IBM AS/400 line

The first computers I used regularly were Apple IIe's in the Library basement when I was in my last year or so of college. They used them.

First machine here was a Windows x386 with, drum roll MS Windows 3.11 and DOS 6.22

Thank you for sharing your first Apple experience

My First Apple was the Motorola PPC Powerbook 12" Tiger 10.4

Owl-53 wrote:

First machine here was a Windows x386 with, drum roll MS Windows 3.11 and DOS 6.22

Thank you for sharing your first Apple experience

My First Apple was the Motorola PPC Powerbook 12" Tiger 10.4

We are old.

Yup and the clock will tick 1 more digit very soon for Moi

Fulling into the 6th cycle of life ( Chinese counting, from moment of conception )

You can get to the bottom of what's in your "System Data" by running a utility like Daisy Disk. It will show you exactly (run it as Administrator). I recently used it and found old iPhone backups, Garmin maps that were leftover from installs to Garmin devices, iOS install files for an iPhone, and some large DMG files. Removed those and saved 50+ GB. Previous instances included old Photos libraries (misclassified as they should have been in the Photos category), folders associated with email software (misclassified as they should have been in the Mail category), and some various user and files associated with various applications (some misclassified).

If you only have 250 GB you will face this problem repeatedly until you replace the computer with one that has decent storage. The only users I know of who can use a 250 GB computer have placed nearly everything they have in iCloud. But that's not for everybody (certainly not for me).

Pål B wrote:

Hmm. According to DaisyDisk the preboot volume is 24.5 GB. Disk Utility says it's 7.15 GB.

Try again if you would

Pål B wrote:

Hmm. According to DaisyDisk the preboot volume is 24.5 GB. Disk Utility says it's 7.15 GB.

You should not touch the Preboot area, it is to ensure your Mac boots properly. If you remove certain items from your Mac, such as Rosetta, that might (or might not) reduce slightly the size of Preboot. The difference in size shown has to do with different bookkeeping in Disk Utility versus Daisy Disk, but none of that 24.5 GB is removable by the user or owner of the Mac unless you want a Mac that won't boot anymore. Some of that 24.5 GB (versus 7.15 GB) is called "System Data" by the Mac while Daisy Disk sorts it slightly differently. But none of that area is user modifiable.

In Daisy Disk, focus your attention on the Users folder, and maybe Applications if there are large things in there you don't use. Also inside Hidden Space you will find snapshots, which in principle can be deleted (I prefer to delete them using Disk Utility, which can also show them) but those usually don't take up much space and they do get recreated by the Mac as it operates.

If Daisy Disk shows "System" as taking up 50 or 60 GB, that is normal. Can't really shrink that. You can only shrink space taken by Applications if you installed non-Apple software. Nothing else should be taking much more than 10 GB (aside from user folders which can be much larger). Your basic problem is a 250 GB disk which is really too small for most usage unless all you do is web browsing and you store most everything in the cloud without mirror copies physically on your physical local drive.

You can move all user Photos and Music libraries to external drives to save space. For me that would be > 100 GB but I have plenty of internal storage so I keep them on the internal drive. And all your documents can be put in iCloud if there is a lot of room going for those. I prefer to keep physical copies on my Mac. I think getting a computer with 1 TB or more is a must nowadays. With 250 GB your options are somewhat limited.

Good work there 👍

But something of interest that may or may not be important

OP wrote " Disk Utility says it's 7.15 GB. "

The values seem about right but the method it is being reported in not

Unless I am mistaken which is possible

Disk Utilities would not report the Preboot in drive structure

Just saying

It isn't easy to find but Disk Utility does show a Preboot size, but it counts things up different than Daisy Disk so Daisy Disk shows that "Preboot" as about 25 GB. I see this on multiple Macs and the OP also sees it. Either way, that is not user shrinkable space, regardless of how it is counted or binned. I think Disk Utility counts it at 7 GB and the other 18 GB is bokkkept as "System Data," another reason "System Data" sometimes is larger than people expect. I think these details can vary with Mac model and with specific version of the MacOS.

Yikes, a new pair to Trifocals are in-order, lol

Making a appointment as we speak, lol

Thanks again and keep up the excellent work