# Explore Disk: a disk space map that shows what’s taking up space on your Mac

Explore Disk is OneMacTools’ disk space map for Mac. It measures every folder, biggest first, starting at your home folder, a drive or your clouds, and shows them as a list or as a map of boxes sized by the space they use. Each item is labelled (Yours, App data, Cache, Build files, Apps or macOS), so you can see what’s taking up space and only trash what’s safe to.

## How to open Explore Disk

1. Open [Mac Clean Up](https://www.onemactools.com/docs/mac-storage-cleanup-tool) from the sidebar (⇧⌘K).
2. In the **Storage** panel at the top, click **Explore Disk**.
3. Explore Disk opens in its own sheet, measuring your home folder. Click **Done** (or press Esc) to close it.

It opens on your home folder because that’s where almost everything you can act on lives. The first measurement of a big folder can take a few seconds; you’ll see “Measuring …” until it’s done.

## Reading the list view

The list shows everything directly inside the current folder, biggest first. Empty items and symbolic links are left out. Each row has:

| Part of the row | What it tells you |
| --- | --- |
| Icon and name | The Finder icon and name. Apps and other packages are shown as one item rather than folders you can open. |
| Label | What the item is: **Yours**, **App data**, **Cache (rebuilds)**, **Build files**, **Apps** or **macOS**. |
| Size bar | How big it is compared with everything else in this folder, coloured by its label. |
| Size | The space it actually takes on disk. |
| Magnifying glass | **Show in Finder**. |
| Bin | **Move to Trash…**, only for items labelled Yours, Cache or Build files. |

Double-click a folder to open it, or right-click for **Open** and **Show in Finder**. The breadcrumb trail above the list (**Home › Library › Caches**) shows where you are; click any part of it to go back up.

Measurements are kept while the sheet is open, so going back up a level is instant. After you trash something, the folders above it are measured again so the sizes stay right.

## The disk space map view

Switch the **List / Map** control at the top to **Map** to see the same folder as boxes, each sized by the space it uses (a treemap). The biggest box is the folder you should look at first. It answers “what’s taking up space on my Mac?” faster than any list.

- Boxes are coloured by label, the same as the list: blue for Yours, purple for App data, green for Cache, teal for Build files, orange for Apps and grey for macOS.
- Names and sizes are written inside boxes big enough to hold them. Hover over any box to see its name and size.
- Double-click a box to open that folder and map what’s inside it.
- The 80 biggest items each get a box; everything smaller shares one grey box called **Everything else**.

To act on a box, switch back to **List**: the Trash and Finder buttons live there, so a stray click on the map can never move anything.

![OneMacTools Explore Disk showing clouds as a map, each box sized by the space it uses](https://www.onemactools.com/screens/disk-map.png)
*Explore Disk: every cloud as a map.*

## What the labels mean, and what you can trash

The label decides whether the bin button works. Explore Disk only offers the Trash for things that are yours, or that rebuild themselves.

| Label | What it covers | Can be trashed here? |
| --- | --- | --- |
| **Yours** | Your own folders and files in your home folder: Documents, Desktop, Movies and so on. | Yes, after a warning |
| **Cache (rebuilds)** | Your Library’s Caches folder, tools’ caches such as .cache, and download caches like .npm that are fetched again when needed. | Yes |
| **Build files** | Build folders inside a project, such as node_modules next to a package.json. | Yes |
| **App data** | The rest of your Library, and hidden folders tools keep in your home folder for their settings and data. | No |
| **Apps** | Applications, and apps in your own Applications folder. | No |
| **macOS** | System folders (/System, /Library, /usr, /private and the like). | No |

Hovering over a disabled bin explains why: “Not offered here: it belongs to macOS or an app”. To remove an app’s data, remove the app; for leftovers from apps you’ve already deleted, use the System Data review below.

### What happens when you trash something

Clicking the bin asks first: “Move “Old exports” (12.4 GB) to the Trash?”. For your own files it adds “These are your own files. Check you don’t need them”; for caches and build files, “It’s rebuilt when needed.” The item goes to the Trash, the bottom line confirms it, and History records it under Mac Clean Up as **Explore Disk**, with **Put Back** until you empty the Trash.

## Start at: your home folder, another drive, or your clouds

The **Start at** menu chooses where to measure from:

- **Home folder**, the default.
- **Each drive** connected to your Mac, by name, including your startup disk. Starting at the startup disk shows the whole disk, including macOS’s folders (labelled macOS and never offered for the Trash). On other drives everything is labelled macOS too, so nothing is offered for the Trash there; use **Show in Finder**.
- **Clouds (from Files)**, when [Files](https://www.onemactools.com/docs/search-all-cloud-files-mac) is turned on.

### The clouds view

**Clouds** shows each cloud Files covers (iCloud Drive, Google Drive, OneDrive, Dropbox, Box) and This Mac as boxes or rows sized by how much each one holds. If one service has more than one account or folder, each gets its own box, such as “OneDrive · Personal”. Double-click a cloud to see its folders.

Sizes here come from Files’ index and **include files that are only in the cloud**, so they show how much each cloud holds, not how much it takes on your Mac. Nothing is downloaded to measure them.

> **Careful:** Nothing can be trashed from the clouds view. Deleting a file in a cloud folder deletes it from that cloud, so Explore Disk only offers **Show in Finder** there. To clear cloud duplicates safely, use **Copies across your clouds** in Mac Clean Up.

## How to review System Data on Mac

System Data is usually the biggest grey part of the storage bar, and the hardest to explain. Explore Disk’s home view shows your Library folder, but the clearer way in is the storage panel itself:

1. In Mac Clean Up’s **Storage** panel, click **System Data**.
2. Read the parts under **Inside System Data**: **App caches**, **Logs**, **App data**, **Virtual memory**, **Sleep image**, local snapshots and **Everything else**, each with its size and a plain description.
3. Click **Review** next to **App caches** or **Logs** to jump to those Clean Up groups, or next to **App data** or **Everything else** to open a review sheet.
4. In the sheet, tick the items you want to remove and click **Move N to Trash…**.

The review sheet lists folders over 1 MB, biggest first, each with a badge:

| Badge | Meaning | Can be ticked? |
| --- | --- | --- |
| **Leftover** | No app on this Mac uses it, and it hasn’t changed in months or years. | Yes |
| **Rebuilds itself** | A download or build cache that’s recreated when needed, such as npm’s or Gradle’s. | Yes |
| **Old backup** | An iPhone or iPad backup more than three months old. | Yes |
| **In use** | Belongs to an app you have, or to macOS. Shown so you know what it is. | No (lock icon) |

**Everything else** also explains hidden tool folders in plain words, often with the command that cleans them properly (for example, “docker system prune” for Docker, or “ollama rm” for unused local AI models). If Xcode is installed, **Simulator devices** has a **Delete unavailable simulators** button. **Virtual memory**, **Sleep image** and snapshots are marked **Managed by macOS**: macOS shrinks or deletes them on its own.

Without Full Disk Access, app containers aren’t listed and some sizes are “at least” figures; see [Full Disk Access](https://www.onemactools.com/docs/mac-privacy-permissions-full-disk-access). For background on what System Data contains, read [What is System Data on Mac?](https://www.onemactools.com/guides/what-is-system-data-on-mac).

## Explore Disk compared with Finder and System Settings

macOS gives you two partial views. **System Settings › General › Storage** shows categories and recommendations but not which folders are big. **Finder** can calculate folder sizes, but one window at a time, and it doesn’t tell you whether a folder is safe to remove.

Explore Disk measures every folder in parallel, sorts biggest first, draws the map, labels each item and refuses to trash anything that belongs to macOS or an app. If you’d rather search for big files by size and type across any folder you choose, the [Large Files Finder](https://www.onemactools.com/tools/large-files-finder) tool does that. For a step-by-step plan to free space, see [How to free up space on a Mac](https://www.onemactools.com/guides/how-to-free-up-space-on-mac).

## Questions

**What’s taking up so much space on my Mac?**
Open Explore Disk, switch to Map and look at the biggest box. Double-click into it until you reach the folder that explains the size. Common culprits are video files in Movies or Downloads, old iPhone backups, developer caches and app data in your Library.

**Is a disk space map the same as a treemap?**
Yes. A treemap draws every folder as a box whose area matches its size, so big folders stand out at a glance. Explore Disk’s Map view is a treemap of the current folder, and double-clicking a box opens the next level down.

**Why can’t I trash some folders in Explore Disk?**
Only items labelled Yours, Cache (rebuilds) or Build files can be moved to the Trash. App data, Apps and macOS items belong to an app or to the system, and deleting them can lose data or break the app. Remove the app instead, or use the System Data review for leftovers.

**Do cloud sizes in Explore Disk mean files are on my Mac?**
No. The Clouds view includes files that are only in the cloud, so it shows how much each cloud holds, not how much disk space it uses. Files that are only in the cloud take no space on your Mac.

**Can I put back something I trashed from Explore Disk?**
Yes, until you empty the Trash. It’s recorded in History under Mac Clean Up as Explore Disk, with a Put Back button that returns it to where it was.

**Why does Explore Disk need Full Disk Access?**
Some folders, such as Mail, Messages, Safari data and app containers, are protected by macOS. Without Full Disk Access they can’t be measured, so their sizes are missing or marked as at least. OneMacTools only reads file sizes there.

Source: https://www.onemactools.com/docs/explore-disk-space-map-mac (updated 2026-10-24)