How to Account for Purgeable Disk Content

free space is the available minus the purgeable

etresoft sums it up here—

“The "available" storage is the amount of used storage that the operating system could automatically delete if it felt that it was really necessary. The "free" storage is the amount that you can actually use for something.

There are system processes that run in the background and automatically delete some of the "available" storage and convert it to "free". If you completely run out of storage, then those system processes will try a little harder. When you "delete" files you are just hinting to the operating system that you don't need those files anymore. The operating system will eventually remove them, but on its own schedule.”

mr88cet wrote:

Macintosh HD info says:

https://discussions.apple.com/content/attachment/25ccdd39-25e4-4c82-8e7d-b6710986ff19

What I think• this is saying is:

The "Used" space includes the "purgeable" files, which MacOS will delete if more space is needed.

• I have 903.54GB (almost half of the disk) of free/unused/available space for new stuff.

The real amount of space used• is 1364GB - 280GB = 1,084 GB.

• That 1,084 real mount of used space, plus 904GB of empty space adds up to 1,988, or about the 2TB capacity of the disk.

Did I psych that out correctly?

what exactly is the mystery here?