See what's eating your disk — at a glance. A fast, native macOS disk usage analyzer that turns a folder or volume into a sortable tree and an interactive treemap, so you can find the space hogs and reclaim gigabytes in seconds.
MacStorageAtlas is a free, open-source disk space analyzer for macOS — a native WinDirStat, DaisyDisk, and GrandPerspective alternative for Apple Silicon and Intel Macs. If you're wondering what is using my disk space on Mac and want to free up storage, it scans folders and volumes and visualizes the results as a sortable folder tree, a proportional treemap, file-type statistics, and a list of the largest files — so you can find the space hogs and reclaim gigabytes in seconds.
Every scan gives you two synchronized views: a folder tree sorted by size and a proportional treemap where the biggest blocks are the biggest consumers. Click a block to inspect it — name, full path, and size — and jump straight to it.
Scanning is fully async and streams progress as it runs: current path, file and folder counts, and bytes scanned so far. Big volumes (hundreds of thousands of files) stay responsive, and a single click cancels — partial results stay visible.
Two dedicated tabs answer the questions that matter: which kinds of files take up the most room? and what are the single biggest files on disk? — each with counts, sizes, and full paths.
| File types | Largest files |
|---|---|
 |
 |
Found something to clean up? Reveal any item in Finder, or move it to the Trash after a confirmation. Files are never permanently deleted — they go to the Trash, so nothing is lost by accident.
Fine-tune what gets counted: scan inside .app bundles (or treat them as single
items), include hidden files, and follow symbolic links. By default sizes reflect
the space files actually occupy on disk, so undownloaded cloud placeholders
(iCloud Drive, OneDrive, kDrive) count as roughly zero — switch to logical file
size if you prefer. Preferences and recent scan locations are remembered between
runs.
- Select and scan any folder or volume with live progress reporting, and cancel a running scan at any time.
- Browse results as a folder tree sorted by size, or as an interactive treemap.
- See storage broken down by file type and a list of the largest files.
- Search and filter scanned items by name or path.
- Reveal items in Finder or move them safely to the Trash.
- Inspect files and folders that couldn't be scanned, and copy their paths to the clipboard.
- Configurable scanning: hidden files, symbolic links,
.apppackage expansion, and real on-disk vs. logical size measurement. - Remembers your scanner preferences and recent scan locations between runs.
- Modern, native-feeling UI that follows the system light/dark appearance, with a responsive treemap and a live scan-progress overlay.
Screenshots above show MacStorageAtlas analyzing its own project folder — build artifacts included — which is why
.pdb,.dll, and.dmgfiles dominate the breakdown.
Branding artwork lives under
src/MacStorageAtlas.App/Assets/:app.ico(window icon),icon.png(1024×1024 master), andMacStorageAtlas.icnsfor macOS app bundling.
Looking for a free DaisyDisk alternative or a WinDirStat for Mac? MacStorageAtlas focuses on the essentials — a fast scan, a treemap, and safe cleanup — without a subscription or a price tag.
| MacStorageAtlas | DaisyDisk | GrandPerspective | WinDirStat | |
|---|---|---|---|---|
| Platform | macOS (arm64 + x64) | macOS | macOS | Windows |
| Price | Free & open source | Paid | Free | Free |
| Treemap view | ✅ | ✅ | ✅ | ✅ |
| Folder tree | ✅ | — | — | ✅ |
| File-type breakdown | ✅ | — | — | ✅ |
| Real on-disk size (cloud-aware) | ✅ | — | — | — |
- macOS
- .NET 10 SDK
- Avalonia templates are not required to build or run; all dependencies are restored from NuGet.
dotnet restore
dotnet build --no-restoredotnet test --no-builddotnet run --project src/MacStorageAtlas.AppRun the packaging script from the repository root. It publishes a self-contained
Release build, wraps it in a MacStorageAtlas.app bundle (with the .icns app
icon), and creates a DMG with a drag-to-Applications shortcut.
./build-dmg.sh # Apple Silicon (default) → MacStorageAtlas.dmg
./build-dmg.sh arm64 # Apple Silicon (osx-arm64)
./build-dmg.sh x64 # Intel (osx-x64)
./build-dmg.sh both # both architectures, one DMG eachWhen building both, the DMGs are named per architecture
(MacStorageAtlas-osx-arm64.dmg and MacStorageAtlas-osx-x64.dmg). Each build
is self-contained and does not run under Rosetta on the other architecture —
pick the DMG that matches the target Mac.
⚠️ Unsigned & un-notarized buildThis DMG is not code-signed or notarized, because the project has no paid Apple Developer account. macOS Gatekeeper will therefore block the app on first launch ("MacStorageAtlas is damaged and can't be opened" / "cannot be opened because Apple cannot check it for malicious software").
To run it anyway, either:
Right-click the app in
/Applications→ Open → confirm Open in the dialog, orRemove the quarantine attribute from a terminal:
xattr -dr com.apple.quarantine /Applications/MacStorageAtlas.appOnly do this for builds you trust and compiled yourself.
src/
MacStorageAtlas.App Avalonia UI and MVVM shell
MacStorageAtlas.Core disk scanning and domain logic
MacStorageAtlas.Rendering treemap layout logic
MacStorageAtlas.Platform.Mac macOS-specific integrations (reveal, trash, dock icon)
tests/
MacStorageAtlas.Tests NUnit tests
- Product backlog and feature specifications:
docs/FEATURES.md - macOS packaging and distribution:
docs/PACKAGING.md
Released under the MIT License.
Keywords: macOS disk usage analyzer · disk space analyzer for Mac · what is using my disk space on Mac · free up disk space macOS · WinDirStat for Mac · DaisyDisk alternative · GrandPerspective alternative · treemap disk visualizer · find largest files Mac · Apple Silicon disk cleanup · open source Mac storage tool.