Missing storage space in SSD

luka.al wrote:

I was wondering if I should have erased the parent drive, but it sounded risky.

Well, in your original post, you said "I recently did a clean install of Catalina because I kept running out of space". It sounds like you had a problem before, but then didn't erase the drive. One problem with the new APFS drives it that people stop at the volume level. Volumes mean nothing on APFS. If you need to erase the drive, you have to remove the volumes and all the containers. Only then can you really repartition the drive.

Clean install—

Could be the SSD has lost some capacity...

Do you need to empty the trash(?)

You can Boot into Recovery (Command R) and from the dropdown menu: Utilities>  Disk Utility> run the First Aid on your Macintosh HD (and the "Macintosh HD-Data" volume as well if Catalina) If errors are found and repaired, run again until no errors reported.

ref: About the read-only system volume in macOS Catalina - https://support.apple.com/en-us/HT210650

How to free up storage space on your Mac - Apple Support

https://support.apple.com/en-us/HT206996

User tip: "Other and What Can I Do About It ?"

https://discussions.apple.com/docs/DOC-5142

Try something likeOmniDiskSweeper for a GUI to get a good look at itemized file size and location:

OmniDiskSweeper http://www.omnigroup.com/more

Others for example—

Disk Inventory X: http://www.derlien.com/ (takes forever to load up.)

Grand Perspective: http://grandperspectiv.sourceforge.net/

Or alternatively from the Terminal.app, more detail copy and paste the command line:

File size, and finding missing GB— list the items in the home folder with the sizes, including invisible items.

sudo du -h -d 1 ~/

File size, and finding missing GB —will list the items in root with the sizes, including invisible items.

sudo du -h -d 1 /

luka.al wrote:

Isn't 30 GB a lot to loose?

I empty the trash regularly, delete unnecessary files, and just did a clean install. I ran that command and the biggest file is the Photos library, which is 17 GB.

What I can't figure out is why the top level SSD says it has a 121 GB capacity, and the containers only have the 95 GB between the two of them. Is there another hidden volume I can't find and how could I erase it?

and what did  Disk Utility> run the First Aid report???

Unless you mucked up an erase/reformat/reinitialize of the parent drive— you would expect a clean install to cover all available space.

This would be DiskUtility>View>Show all Devices> here you select the "parent" drive (ie the disk level,) not the Container level or Volume level when you fall back or reinstall from scratch.

There is always the possiblity the drive is inadequate in some fashion.

the terminal output makes one question...