MBP available space

in these days I was checking the available space on my MBP 250G, and I see some behavior that baffles me.

  1. After restarting the machine, after several secs, available space stands at 189G.

  2. I do some work (Xojo o whatever apps), but without creating new files or pictures. After a couple of hours, available space becomes 192.86G
    If I use Safari, before quitting I clear the cache.

  3. I put the machine to sleep, and after three hours, available space is 191G

And so on and so forth, always in the range of 189 - 193: up and down, up and down.

So I wonder, what is triggering those gigas when I don’t create or download files? Just curious.


I’ve seen this, too. macOS is doing some strange things there. Have a look at the hard disk with Daisy Disk. You will see a lot of reserved space in “hidden objects” or similar. On my 256 GB SSD 27 are “hidden objects”. A restart usually improves things for a short while.

TimeMachine makes snapshots and deletes those later which causes free space to fluctuate.

The worst is FireFox: it keeps in hard disk your navigation data and some other stuff.

Also, the OS saves data in a multitude of files 'even files for Xojo / Xojo projects…

128GB (or 2556GB) SSD are far too low excepted if you do not have data to deal with (courier, internet, watching videos stored in external)…
512GB SSD is a minimum, things start to be OK at 1TB.

And this have to be done at buy time: no second chance (for a company where there is a second chance is…)

Yup - it’s the APFS SnapShots. Also OS updates may cause a SnapShot to be created.
You can list (and manually delete) them in Terminal - a more convenient way is Carbon Copy Cloner which has that functionality built-in, too.

Good to know that I’m in good company.