Related Article: What is 'Other' and 'Purgeable' in About This Mac?

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

How do you purge purgeable space on an SDD mac?

I have a 13" MacBook Air with 250GB SDD drive. My disk started nearing capacity lately so I decided to try the new feature of moving Documents and Desktop files to iCloud. That seemed to work as all files are now in iCloud. At that point I decided to import photos into Photos, also taking advantage of its ability to store files in iCloud and automatically manage memory usage on the SDD. After doing some imports in Photos it alerted me that my disk is almost full. When looking at Storage, it appears that 100GB of space is 'Purgeable' and that I have nearly no 'free' space remaining. The documentation makes it sound like this is exactly what iCloud storage is for - to move rarely used files off of local storage to make room for new files. Unfortunately I am not able to purge this purgeable space and the OS seems to not make use of it for new files either, so it amounts to dead space. I'm not able to import new photos, or even create new files due to lack of available disk space.


I am not running time machine, and I already manually purged all files that were still in Downloads. There are no other files to purge as they are already in iCloud. Any suggestions for how I can make this work without bringing all my files back from iCloud and manually purging more of them?

MacBook Air, macOS Sierra (10.12.2)

Posted on Jan 22, 2017 6:51 PM

Reply
36 replies

Jan 18, 2018 9:52 AM in response to William Lloyd

This does work and may help someone Googling this issue...


Since OSX doesn't seem to free the "Purgeable" space reliably especially when using "finder" do this instead...


1. Open terminal (Click Launcher and type "terminal")

2. Type without quotes "cat /dev/zero > Purge.txt"

3. Wait a few minutes

4. Press Control-C to stop "cat"

5. Type without quotes "rm Purge.txt"

6. Close terminal and check your disk space (Purgeable will be growing again but should be in the low MBs not GBs).

Jan 24, 2018 8:31 AM in response to v2_

I'm on 10.13.3 currently. The function above does not change anything - both free space and purgeable space remain the same. However, the used space and available space add up to the size of disk, so "purgeable" space is not subtracted from the free space (again, on APFS). Perhaps, purgeable is some side effect of sparse file storage, which is not actually used?

Jan 25, 2018 6:32 AM in response to ncr_support

It does work but the filesystem free space has to get to the point where it realizes it needs more space for the text file being written by cat. The Mac Pro this was used on had only 4GB of space left on the 512GB SSD and the purgeable space was ~198GB. After writing the text file for a few minutes the puregable space went to ~38MB (and growing) and free space to ~202GB. The text file was about 3GB in size when it was deleted (rm step). This was on an HFS+ filesystem.


I wouldn't use this unless absolutely necessary as it will use up the SSD write cycles if over used.


I originally was trying to copy a 160GB VMWare VMDK file from a backup drive to the internal SSD when running into this problem. Finder refused to copy the file due to lack of space. Something had to trigger purgeable space to be purged so, I tried the cat option in terminal (Linux non-destructive, free space drive zeroing knowledge coming in handy) surprisingly it worked.


Finder must check for space before trying to copy the file and does not "notify" the filesystem that a large file is about to be copied so that purgeable space can be purged before the copy starts, instead Finder throws an error that there is not enough space.

Jan 25, 2018 7:17 AM in response to ncr_support

Since your volume is APFS, it's possible the purgeable data is Time Machine snapshots.


Have you tried:

Open Terminal

Type: tmutil listlocalsnapshots / (if you see a lot of these you can thin them down or delete them)

Type: tmutil thinlocalsnapshots / (thin down)

or

Type: tmutil thinlocalsnapshots / 9999999999 1 (deletes all but maybe the newest snapshot with urgency high)

Mar 3, 2018 3:16 AM in response to dbaluta

I was annoyed by the not directly visible free space.


This commands in "Terminal" helped:


at start about 21G free (70G purgeable)


I created file of 30G in my home directory:

dd if=/dev/zero of=blowup bs=10m count=30720


Checking the file system usage:

df -Ph /

it ran up to 97% and kept fluctuating a bit


After the creation of the file (the dd command finished) I simply "cleaned" the file (not sure removing would have worked, this did):

> blowup


After that (takes some time) the size of the file is 0, and the file system usage starts dropping - and I got more free from purgeable (only 3G left) - so size of file to create is a bit trial and error (worst that can happen is that file system actually does fill up , the "> blowup" will resolve that quite soon)

Mar 6, 2018 8:31 AM in response to v2_

Thank you V2_ This worked like a dream on my 250Gb SSD Macbook Pro which was hogging 144GB 'Purgeable' and not letting me back up my iPhone, despite moving the 60Gb iPhoto's db off onto another disc. Thank you a Gzillion times, its disappointing as Im used to dual working on Windows PC's and my Mac, that its not easy to just 'Purge' unused space in macOS High Sierra. Frankly very disappointing Apple

How do you purge purgeable space on an SDD mac?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.