MacOS stealing your disk space?

Ever wondered where your notoriously rare disk space on your Apple device might be gone?

If you like me come from the linux universe you might wonder - or maybe even freak out about - why the heck your admittingly small SDD is already running out of space while you can't remember installing a dozen of blockbuster video games lately.

Where to check what is stealing space

• At first you might want to have an overview about what ist actually on your disk. Open the MacOS Settings, there go to General > Disk (maybe it's labeled differently? In german it's Allgemein > Speicher).
• The coloured bar at the top of this view might show you usage of a lot of disk space.
• A comprehensive list of data types and applications is under the recommendations regarding paper bin and iCloud.

  • clicking the i-icon behind each item opens another view in which you can take a closer look into that item and maybe delete some not longer needed garbage
  • e.g. you might check the Apps for space eaters that can take several GB of space like games, iMovie, electron based apps like chat clients etc..
  • or check your documents by size and remove e.g. old video files you archived on external disks before etc.

    Systemdata ate my hamster ... err ... disk space

    But still ... there will be that last item called systemdata (Systemdaten in german) which is huuuuuuge and won't shrink by all that deleting efforts. As you notice there's no i-button behind that entry and so no further hint how to reduce those unexplainable mountain of data. Which can't be part of the core system as that's shown above with around 25GB usually. So what's this garbage?! In deed there's also garbage as one might put it - e.g. caches the system uses to speed up your user experience. And MacOS follows the idea that you paid for the disk space - why not use it?! I.e. as long as there's free space on your disk MacOS wil fill it with caches, temporary stuff and ...

    TimeMachine Snapshots!

    You won't get rid of all that systemdata but nevertheless you can reclaim a lot of it by just removing those local TimeMachine snapshots stored in it. Usually you won't save your TM snapshots on your local machine, will you? If you do, you might consider plugging in a simple external disk drive and link your TimeMachine setup to it. But even then MacOS will save so many snapshots also locally as there's unused space on your machine! And I didn't find an easy Point&Click-way to delete them yet. But I found that article ...

    tmutil in the Terminal

    Get an overview about the local stored snapshots with tmutil listlocalsnapshots /. Which will give you something like

    Snapshots for disk /:
    com.apple.TimeMachine.2026-03-06-202129.local
    com.apple.TimeMachine.2026-04-05-123510.local

    And as I put above that list might contain more items, maybe 5 or more. To free disk space you could delete some or even all of them by typing tmutil deletelocalsnapshots 2026-03-06-202129 and repeat that adapted to every snapshot according to the name pattern.

After that you may check the disk space at the Settings again and find tenth of GB freed again.

The named article states that you also might just uncheck the Back up Automatically box in the TimeMachine settings, wait some minutes and then every local snapshot will be erased and the same amount of space will be free. But I didn't try that yet.