• DaisyDisk Icon
  • DaisyDisk
  • Tech Specs
  • Pricing
  • Support
  • Buy
  • User Guide

    Purgeable space

    What is purgeable space

    When you check how much available disk space you have on your Mac, you’ll find that there’s a chunk of space that is not literally free, but is nevertheless available to applications. In macOS, it’s called “purgeable space”.

    The purgeable space mostly consists of local snapshots of Time Machine, and also caches, sleep images, swap files and other temporary system files.

    When an application requests more disk space than is currently free, the system automatically and instantly reclaims the corresponding amount from the purgeable space.

    Or else, when there is no deficit of free space, macOS allows the purgeable space to pile up to as much as 80% of disk’s capacity, by design.

    The system calculates the current amount of purgeable space asynchronously in the background, and often there can be a significant delay between your action and its effect on the purgeable space, from a few seconds to a few minutes.

    Revealing purgeable space in DaisyDisk

    Starting from macOS High Sierra and APFS, the purgeable space is located outside of any scannable area, even with raised permissions. Instead, DaisyDisk provides a macro-level view and deletion of the purgeable space.

    After scanning, you can see the purgeable space when you expand the hidden space item.

    Purgeable space

    Before macOS High Sierra, the main component of the purgeable space — the local snapshots of Time Machine — could be revealed in restricted folder at path `/.MobileBackups` after scanning as administrator.

    In disks overview, DaisyDisk includes the purgeable space into the free space, exactly as Finder does. This allows you to understand how much space is maximally available on a disk, at a glance.

    Reclaiming purgeable space

    The purgeable space is there by design of macOS. In most cases you don’t have to worry about it, and just let it be — it will be reclaimed automatically as needed.

    However, in certain cases, a forced purge may be necessary. For example, when you need to free up a certain amount of disk space to create a partition, or simply when something goes wrong and the purgeable space seems to get out of control.

    With DaisyDisk you can forcedly reclaim the purgeable space by dragging the purgeable space item to the Collector, as you would do to delete a regular file or folder.

    Reclaiming purgeable space

    This feature is not available in the Mac App Store edition of DaisyDisk. More about DaisyDisk versions.

    Note that depending on the amount of purgeable space, the purging may take 2-10 minutes.

    Also please allow a couple of minutes afterwards, until the system recalculates the new amount of purgeable space. When done, DaisyDisk will automatically refresh the purgeable space item, without rescanning.

    Also note that a certain amount of purgeable space (7-10 GB) will remain after purging, because macOS may not be able to release all of it, and also because the system will immediately begin building new temporary files.

    Viewing purgeable space in macOS

    Because the purgeable space is instantly reclaimable, macOS counts it toward the available space, i.e. as if it was free. The resulting figure (free + purgeable) is displayed as “available” in many places in macOS and its standard apps, such as Finder, About This Mac and Disk Utility.

    Here’s how it looks in Finder’s Get Info window:

    Finder’s Get Info

    In About This Mac on macOS High Sierra the purgeable space is included into the System category, which can often be confusing, because the System appears to take too much space, and the available space written in text is no longer proportional to the bar’s empty part.

    System taking too much space in About This Mac on macOS High Sierra"

    On macOS Sierra, purgeable space used to have its own Purgeable category in About This Mac.

    Purgeable in About This Mac on macOS Sierra

    Table of Content

    Using DaisyDisk

    • Disk overview, scanning
    • Understanding the disk map
    • Locating space wasters
    • Previewing file content and details
    • Deleting files

    Advanced features

    • Hidden space
    • Purgeable space
    • Other volumes
    • Restricted folders
    • Local APFS snapshots
    • Full Disk Access
    • Scanning as administrator
    • Parallel scanning
    • Scanning cloud storage
    • Keyboard shortcuts and multi-touch gestures
    • Tips & tricks

    License activation

    • Activating the free trial
    • Benefits of buying a DaisyDisk license
    • DaisyDisk editions & license migration
    • Registering your license

    FAQ

    • What is safe to delete?
    • System taking too much space on macOS High Sierra
    • About Apple File System (APFS)
    • Troubleshooting scanning as administrator
    • Undeleting files
    • Time Machine & versions
    • Mismatches with Finder
    • File system not responding (time-out) error
    • Hard links
    • Disk images
    • Problems on remote desktop

    See also

    • Version 4, English
    • Version 3, English
    • Version 2
      • English
      • Русский
    • Version 1, English
    HomeUser GuideVersion 4EnglishPurgeable space

    Links

    • Our store
    • Mac App Store
    • Terms of use
    • Privacy
    • Cloud Privacy

    Support

    • User guide
    • FAQ
    • Find license
    • Get in touch
    • Release log

    Company

    • About
    • Blog
    • Media reviews
    • Affiliate program
    • Versions archive

    Social Networks

    • X
    • Instagram
    • YouTube
    • Facebook
    • Student discount
    © 2008-2025 Software Ambience Corp. All rights reserved. Apple® and Mac® are trademarks of Apple Inc. The media logos are intellectual property of their corresponding copyright and/or trademark holders. DaisyDisk® is a registered trademark of Software Ambience Corp.