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Mac OS How To Remove Purgeable on Hard Drive

by 74 Comments

Can’t Remove Purgeable Disk Space

Note: If you have Mac OS High Sierra installed, you need this guide instead.

When trying to install Bootcamp on my MacBook Pro, I had to delete a lot of files to get enough space to be able to accommodate for a Bootcamp partition on the drive. But even after removing around 60 GB of storage, Mac OS Sierra could still not make a large enough partition for Windows. When checking with Disk Utility it showed that indeed I had enough space, but there was a part called Purgeable that was impossible to move. No tools from Apple are available to handle this, but here’s how I fixed it.

Screenshot of Disk Utility showing Purgeable part of volume

(not actually my disk, forgot to take a screenshot)

Optimize Disk Storage

Apple added a feature called “Optimize Disk Storage” in Mac OS Sierra. The idea is quite good. This feature isn’t well-implemented though. If you have it enabled in System Preferences under iCloud/iCloud Drive settings (which I think is on by default), you essentially have two different values of how much disk space you have available. One “real,” that shows exactly how much there is, and then you have the Purgeable part, that includes software that can be uninstalled on the fly and later restored if enough space is available.

My problem was that Mac OS Sierra refused to remove the Purgeable part of the partition, so when I tried to install Bootcamp, It only showed the “real” free disk space. The problem is, I manually deleted stuff like iMovie and Garageband with the associated files by hand using OmniDiskSweeper, which is a free and excellent application for finding and removing large unused files on your disk. But for some reason, Mac OS Sierra refused to recognize that I had the free disk space. After searching the net, I couldn’t find a good solution. But after a quick hack, I’ve created an easy way of forcing Mac OS to remove the “Purgeable” disk space.

How to remove Purgeable Disk Space

First I created a 20GB file using the Terminal application. It’s easy enough thanks to Mac OS Unix underpinnings. Open the Terminal app, found in the Utilities-folder in Applications. Don’t let the sparse interface scare you; this thing has super powers!

Enter the following:



dd if=/dev/zero of=~/stupidfile.crap bs=20m

The command creates a file named stupidfile.crap using a device available on Unix/Linux, called /dev/zero which sends zeros which we use to create a large file.
You could do a periodic “Get Info” in the Finder to check on how large the file is. Another is to install Brew and use it to install the great tool watch by entering the command

brew install watch

If you do, open a new Terminal window and enter:



watch ls -alh ~/stupidfile.crap

Now we can see how large the file is. When the data is about 10-20GB in size, press ctrl-c in the first window to stop creating a file. You can now quit the Terminal application.

Large file, let’s fill the disk!

So now we have a large file. No need to use the /dev/random function to make a larger file, because it’s faster to duplicate the stupidfile.crap we just created. So go to your home directory, select the file stupidfile.crap and press cmd-d to duplicate the file. Just keep making several duplicates at the same time to speed things up. Now we will make a lot of copies of the file in your home directory. What we are aiming for, is to fill the disk, so the OS starts purging (hence, eating into the “Purgeable” part.)

Sooner or later you’re going to hit the magic wall, and you’ll get messages that the disk is full. Wait awhile and see if it has removed parts of the Purgeable section using /Applications/Utilities/Disk Utility. If the system allocates more free space, keep duplicating our dummy file to fill up the disk. Sooner or later, you will have a full disk with either a very small or nonexistent “Purgeable” section on it.

Time To Turn Off  “Optimize Mac Storage”

Image of System Preferences iCloud Settings DialogNow you can turn off that pesky Optimize Mac Storage function. So go to System Preferences/iCloud, press the iCloud Drive Options button to get to the setting. Deselect “Optimize Mac Storage.”

Now you can remove all the dummy files we created to fill up the disk and voilá, we now have access to all the empty disk space without that stupid Purgeable part there.

So now I could make a more substantial partition for Windows. Why a larger partition for Windows? Games of course!

Image of the Bootcamp Utility

Comments

  4. This might solve the problem short term, but if you have an SSD doesn’t this shorten the lifespan significantly? Could there be a way to trick macOS into thinking it’s full without actually wasting write cycles?

    Reply

    • A one time write to part of the disk blocks won’t have much of an effect. Just think of the virtual memory file that constantly updates on the disk. Or logs from different processes. I don’t think you have to worry about it.

      Reply

  7. Just wanted to say thank you. This was a big help. My problem was directly tied to a large Photos Library that was set to “Optimize,” but wouldn’t let go of the full resolution files. Completely filled my drive. Every time I would copy the “stupidfile” it would shrink the size of my library.

    Reply

  13. I can find the files after I unchecked “Optimize Mac Storage”. Now the files have become part of my “system” storage and are unfindable plus I cannot delete the “system” storage file. This is terrible, it has ruined my computer.

    Reply

  14. Hi, is there any way you could explain this in a little more detail? When I paste “dd if=/dev/random of=~/stupidfile.crap bs=20m” into my terminal, nothing happens.

    Reply

    • I landed up using disk utility, but it seems it was just taking a long time because of the file size. Thank you for your write up.

      Reply

  15. Hi

    I followed this method and it worked like a charm. No need to create dummy files:

    https://www.youtube.com/watch?v=ih3oNmNz9w0

    I.e.
    I disabled “Optimize Mac Storage” under System preferences> iCloud>iCloud Drive
    I then disabled ” Back Up Automatically” under System Preferences> Time Machine
    Restarted Mac, then re-enabled ” Back Up Automatically” under System Preferences> Time Machine

    Purgeable storage is gone!

    Reply

  21. Thanks for providing these details, again learning a lot although it is not solving my problem. I tried to start all these actions in the right sequence and I’m also getting the message that my disk is full but the purgeable space is not getting smaller. Any idea what this could be? So far I didn’t deactivate the “Optimize Mac storage” because I assume you can only do this when the disk free again.

    Reply

    • I guess you didn’t read the disclaimer of not doing this if you don’t know your way around the computer.
      If you followed the instructions it should be in your desktop folder. Otherwise just search in finder…

      Reply

  23. Thanks so much for this, was on the verge of selling my mac to buy a new one because of the storage problem (75GB out of 150GB was purgable)

    Reply

  27. first of all, thanks for that idea! but somehow it didn’t work for me.

    i created a 3GB file and then copied it several times. For some strange reason I was able to create a folder, which was 1.5 TB large?! I only have 500GB disk space. did i do something wrong? any suggestions? Heeeeelp

    Reply

      • Did you read the disclaimer at the beginning of the article, talking about not doing this without enough knowledge? What are you trying to accomplish? Are you doing it for expanding a partition on the hard drive? There’s no other reason for doing this.

        To find the files, go to Finder, do a search by pressing CMD-F. Select the dropdown selector named “kind” and choose “Other.” Search for size and select “File Size”.

        Now enter “File size is greater than 5 GB” or an appropriate size and you should be able to find the files.

        Reply

        • Folks-
          I too got to the same spot. Followed the same instructions and had way more files than possible. Deleted the temp files and no relief. Then I stumbled upon something in reddit related to TimeMachine files that need to be eliminated.

          I made sure I had a good backup.
          Then issued these commands from terminal (Do at your own risk after researching)

          sudo tmutil listlocalsnapshots /
          sudo tmutil thinlocalsnapshots / 999999999999
          sudo tmutil listlocalsnapshots /

          The first and third examples are reports of your disk usage.
          “listlocalsnapshots”

          The 2nd (middle one) actually purges them
          “thinlocalsnapshots”

          That third one will again tell you the files and you’ll see they are gone.

          This was the magic sauce I needed to free up all the purgeable. Once I did that bootcamp ran swimmingly. Even if you have a backup it seems there might be rather large delta files sitting around…

          Cheers!

          Reply

    • i did it in high sierra and worked perfectly – created 100 x 2 gig files (more than i had ) with 100 gig pursuable – great bit of code – might get bootcamp to work now after spending a day trying to sort it 🙂

      Reply

  30. ILL pile on the praise.. Great job. Thanks. Another stupid apple feature that was horribly implemented and as usual they refuse to explain it.

    Reply

    • Ok, I’ll bite.
      Hi Zac Morris!
      You see that wheel between the buttons on your mouse? You can use that to skip parts you don’t want to read.
      Just for fun, I did a quick search on you on the net and it seems like you hate gays and Chinese people and only browse far-right home pages. And yet you post from Beijing in China? Ah, I forgot, you’re studying Chinese medicine.

      Go figure…

      Best of luck with that hate thing you got going…

      Reply

  34. Worked well for me – purgeable bit is gone. By the way – shame on you Apple for giving us all this trouble and making us loose time on such junk. Perhaps we should start sending them invoices for our time spent fixing computers they’ve created?

    Reply

  35. Thank you thank you thank you! This is the best. I had 50 Gigs of purgeable space and the only other options to get rid of it cost like 50 bucks. Thank you so much

    Reply

  38. Oh my god thank you so so so much. This has helped me and now I can finally try to run bootcamp! Thank you soooo much may god bless you with rasberry farms and lights of coasters

    Reply

  39. Most excellent – took me right back to my heady days of UNIX support (some 18 years ago!). Love that it is sitting there right under the OS and enjoyed doing a cp in the xterm at the same time as the duplicate in Finder – Finder was quicker. Great to have real space again. Thank you.

    Reply

  41. I was able to create the file no problem, and while it was growing it was working to fill the available space. However, duplications of the file dont take up any space at all. I also tried a trick copying and duplicating your entire photo library, but the duplications of those also dont take up any space. Help?

    Reply

  43. Btw. thanks for the article! I went from 18GB free to 138GB free on a 256GB disk! Also, OmniDiskSweeper is pretty useful. Thanks!

    Reply

  44. Thank you for the tips! I have macOS 10.13 High Sierra with the new APFS file system (why does Apple force such big changes on to us when upgrading? I should know better…) and because it relies on cloning when making duplicates of files your tip does not seem to work anymore. Been going crazy for hours now.

    I tried this without success: I created several files using /dev/zero instead of /dev/random, disabled time machine backing up automatically, disabled optimisation, recreated spotlight index, went in “about this mac” into the storage, waited for the chart to appear, clicked on “manage”, went to “documents”, deleted them from there, went to the trash in the same window, clicked on “empty trash”, then waited a long time to let the mac do something with the file system. Then the “system” was taking 385 GB instead of 60GB…

    Reply

      • I finally managed!

        Just let the following command make the file grow until it fills the whole space. It will stop on its own.

        dd if=/dev/zero of=~/stupidfile.crap bs=20m

        Then delete it. Then in my case try to make a time machine backup. It will fail and delete the local snapshot!

        Reply

  46. Thanks for the blog.
    On High Sierra the duplication didn’t work. I guess on apfs file system true duplicates are not copies but links.

    Instead of generating random file I also used zero because it’s way much faster:
    dd if=/dev/zero of=~/stupidfilezero.crap bs=20m

    At first it didn’t remove the purge data so I stopped the file and I started another one and that worked:
    dd if=/dev/zero of=~/stupidfilezero2.crap bs=20m

    Also I had to keep closing and opening Disk Utility to get it updated

    Thanks!

    Reply

  50. 09/04/2018 13:54:43 For non techies, latest version of DaisyDisk has a purge/reclaim hidden space / purgeable that gave me back 80 gb on my “slowing to a crawl” mac. I suspect that there were some files in there that were not being “reclaimed” by the OS and this did the trick for me.

    Reply

  51. Hurray for DaisyDisk! Great space visualization tool, and it really will remove Puregeable space. I tried all the methods mentioned above, and often each step resulted in a greater amount of purgeable space than I had before! (Especially the ‘dd’ command to create a huge file till you run out of space. Increased purgeable from 3GB to 50!)

    Also the DaisyDisk documentation made me realize I didn’t really need to delete purgeable space after all. As mentioned by Jack, you only really need to do this if you’re repartitioning. It turns out most of the purgeable space is caches, etc., which really is purgeable. Everything else I had been reading suggested it was iCloud “Optimize This Mac” stuff, and I have all that turned off, so I was getting pretty frustrated trying to figure out where all that purgeable space was coming from.

    Thanks.

    Reply

  52. “This feature isn’t well-implemented dough.”

    Did you mean to say “though”? Or is this an expression I’m unfamiliar with?

    Regardless, thanks for showing how to reclaim that disk space.

    Reply

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