---
title: "APFS · MacMelon"
description: "APFS is the Apple File System used on modern Macs. Clones, snapshots, and space sharing are why free space is not a simple subtraction."
url: "https://macmelon.com/glossary/apfs"
---

# APFS

Apple File System, the default format of modern Mac volumes.

APFS replaced HFS+ on modern Macs. It is copy-on-write. Clones share data until one copy changes. Snapshots preserve a point in time. Volumes on the same container share free space. Those features are why a file copy can be nearly instant and why free space is not always used-minus-size.

You do not configure APFS inside [Disk Housekeeper](https://macmelon.com/apps/disk-housekeeper). You do run into it when the menu bar readout and Storage settings disagree. Read [purgeable space](https://macmelon.com/glossary/purgeable-space) and [APFS snapshot](https://macmelon.com/glossary/apfs-snapshot) before you assume a clean failed.

## Apps

[Make room for what matters. Clear clutter with confidence. ### Disk Housekeeper](https://macmelon.com/apps/disk-housekeeper)

## Related guides

[### How to free up disk space on a Mac](https://macmelon.com/guides/how-to-free-up-disk-space-on-a-mac)

## Related use cases

[### Free up space on a MacBook](https://macmelon.com/use-cases/free-up-space-on-a-macbook)[### Read a savings history](https://macmelon.com/use-cases/read-a-savings-history)

## Related terms

[A point-in-time copy of an APFS volume, used by local Time Machine snapshots and some system updates. ### APFS snapshot](https://macmelon.com/glossary/apfs-snapshot)[Space the system may reclaim, which is not always free for a new file right now. ### Purgeable space](https://macmelon.com/glossary/purgeable-space)[The Storage category macOS uses for files that do not fall into the named buckets. ### System Data](https://macmelon.com/glossary/system-data)