Which fits your needs?
NullDisk: Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports.
SquirrelDisk: People wanting a free open-source GUI across desktop systems and remote storage.
Features, pricing, and workflow
Scroll across to compare
| Feature | NullDisk | SquirrelDisk |
|---|---|---|
| Best fit | Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports. | People wanting a free open-source GUI across desktop systems and remote storage. |
| Visualization | Radial map, treemap, and file list; CLI terminal treemap | Sunburst, treemap, file list, and duplicates |
| Platforms and requirements | Mac app: macOS 14+; CLI: macOS, Linux, Windows | macOS, Windows, Linux |
| Pricing and editions | Direct Mac edition free with reminders; optional $9.99 one-time personal license or team seat removes reminders. App Store terms are separate. | Free; AGPL-3.0 source published on GitHub. |
| Open source | No | Yes |
| Native macOS UI | Yes | Cross-platform interface |
| Cleanup workflow | Review source and action: local Trash, explicit permanent removal, or backup/delete; remote and cloud actions depend on the destination. | Collector offers Trash, permanent removal, secure erase, or backup before deletion. |
| Reports and portability | CLI produces JSON/NDJSON scan reports. Third-party scan files are not directly imported into the Mac GUI. | The current overview does not establish an interoperable scan-report format. Preserve paths, duplicate decisions, and remote source settings separately. |
NullDisk: what stands out
A good fit for Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports.
NullDisk: strengths
- Radial and treemap views with local, SSH, and cloud sources
- Git-aware development cleanup for generated output and eligible worktrees
- Native Mac UI plus terminal UI and JSON/NDJSON CLI reports
Considerations
- Desktop GUI requires macOS 14+; Linux/Windows use the separate CLI
- Mac app sends anonymous usage telemetry; no in-app opt-out at this review
- No content-based duplicate finder; allocated bytes are not a guaranteed recovery total
SquirrelDisk: what stands out
A good fit for people wanting a free open-source GUI across desktop systems and remote storage.
SquirrelDisk: strengths
- Live maps and a staged removal collector
- Content-based duplicate search
- SSH and rclone-backed cloud storage
Considerations
- Uses a cross-platform Rust interface rather than SwiftUI
- Permanent deletion and secure erase require deliberate review
- Cloud/SSH actions depend on provider and remote-system support
For a useful comparison on your own drive, match the scan root, access permissions, and size mode. Chart style changes how you explore the results; it does not by itself establish measurement accuracy.
Common questions
When should I choose NullDisk?
A good fit for Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports. Direct Mac edition free with reminders; optional $9.99 one-time personal license or team seat removes reminders. App Store terms are separate.
When should I choose SquirrelDisk?
A good fit for people wanting a free open-source GUI across desktop systems and remote storage. Free; AGPL-3.0 source published on GitHub.
Will both apps show the same size?
Not necessarily. Match the scan root, permissions, exclusions, and logical/allocated-size mode. Hard links, APFS clones, snapshots, sparse files, and cloud placeholders can change totals. A reported size is not a guaranteed amount recovered after deletion.