Purging Purgeable Data

The amount of free space on your hard drive is in question.

Some application says you don't have enough free space to do something with 1 GB of data (such as iTunes cannot backup your iPhone to the local computer!).

Finder says something like 200 GB are free. Yay! no....

Disk Utility says 200 GB are free, but 199.9 GB are Purgeable. Those numbers are made up. See my screenshot for my actual situation.

If you're like me, you thought, "Where's the Purge button?" Well, the only one we find is in the back of our throat.

You read articles.

You do not have Optimize Mac Storage turned on and never have.

You have hooked your computer up to your Time Machine backup and let it run overnight, plugged in and turned on without closing the lid (just in case, you know, something wtvrs.)

You read MOAR articles.

You turn on Optimize Mac Storage. You let it do its thing for a day. Nothing changes. You turn it back off. You wait a day. Nothing changes.

You turn off Automatic Backups in Time Machine. You reboot. You wait a day. Nothing changes.

Then you start reading all sorts of fun things in Terminal

tmutil disablelocal is an Unrecognized verb. Nothing else works. And then you start to mash the info together...

HERE IS WHAT I CAME UP WITH:

Open Terminal.

df -h

See list of volumes / drives. Find the one you care about. It is not always /dev/disk1. For example, here's mine:

Filesystem Size Used Avail Capacity iused ifree %iused Mounted on

/dev/disk1s1 605Gi 420Gi 184Gi 70% 1268158 9223372036853507649 0% /

devfs 185Ki 185Ki 0Bi 100% 640 0 100% /dev

/dev/disk1s4 605Gi 1.0Gi 184Gi 1% 1 9223372036854775806 0% /private/var/vm

/dev/disk0s3 94Gi 59Gi 35Gi 64% 242895 36453481 1% /Volumes/BOOTCAMP

map -hosts 0Bi 0Bi 0Bi 100% 0 0 100% /net

map auto_home 0Bi 0Bi 0Bi 100% 0 0 100% /home

I find that /dev/disk1s1 is my largest volume and the stats noted corespond to my actual local drive space usage.

Now do this:

diskutil secureErase freespace 0 /dev/disk1s1

See something like a percentage meter and such. Let the thing do its work. When it is done is looks like this:

Started erase on disk1s1 Macintosh HD

Creating a temporary file

Securely erasing a file

Creating a secondary temporary file

Mounting disk

Finished erase on disk1s1 Macintosh HD

NOW go look at Finder and Disk Utility.

HEY-OHHHHH!!!! It worked for me. BUT you really should make sure the simpler things do not work for you, first.

Dear Apple Developers:

Statistically NOBODY knows that local Time Machine Snapshots are being made.

Your OS doesn't just make room for new data by eliminating snapshots on the fly. It might be supposed to, but it don't.

So, since we can't see your magic hidden data and you don't give us an option to work this out, we end up screwed and having to go muck about in the Terminal. FOR A WEEK. Just so that we can, in my case, make a complete local backup of my iPhone SO THAT I CAN WIPE RESET AND REINSTALL IT... *AGAIN*.

No Love,

All Of Us.

PS - Stop doing things like this.