Your Mac shows a low-disk warning, or things just feel slower than they used to. Before you start deleting files you might regret removing, the right first step is to actually see what's taking up space on your Mac — broken down by folder, file type, and size. This guide walks through every built-in method macOS offers, plus the fastest way to get a visual picture of your disk.
Start Here: The macOS Storage Overview
Apple gives you a high-level breakdown of your storage right from System Settings. It is a useful starting point, but it deliberately hides detail — so treat it as a map, not a diagnosis.
- Open Apple menu → System Settings → General → Storage (macOS Ventura 13 and later). On Monterey 12, go to Apple menu → About This Mac → Storage.
- Wait a few seconds for the bar chart to finish calculating. The colored segments represent categories like Applications, System Data, Documents, and iCloud Drive.
- Click the Info (i) button next to any category to see which files Apple put there and to access the built-in recommendations (Empty Trash Automatically, Reduce Clutter, etc.).
The biggest frustration with this view is the catch-all System Data category. It can balloon to 30–80 GB on a well-used Mac and includes caches, logs, Time Machine local snapshots, and files macOS cannot easily categorize. Apple does not give you a drill-down for it, which is why the next steps matter.
How to See What's Using Storage on Your Mac with Finder
Finder's built-in sort and column view is the simplest way to find large files without any extra software.
- Open a Finder window and press Command-Shift-H to go to your Home folder.
- Switch to List view (Command-2) and choose View → Show View Options (Command-J).
- Check Calculate all sizes and close the panel. Finder will now show folder sizes — it takes a moment to calculate.
- Click the Size column header to sort largest first. Drill into any folder that surprises you.
Common culprits you will find this way: ~/Library/Application Support (app data, often large for video editors or databases), ~/Library/Caches (browser and app caches), ~/Movies (Final Cut or screen recordings), and ~/Downloads (forgotten archives).
Note: Finder does not show hidden folders like /private/var or the system's own /Library. To see those, you need Terminal or a dedicated tool.
Check Mac Storage Usage from Terminal
Terminal gives you full visibility into every folder, including hidden system paths. The two most useful commands are du (disk usage) and ncdu (an interactive version via Homebrew).
Quick top-level scan with du
Run this in Terminal to see the largest top-level directories in your home folder, sorted by size:
du -sh ~//* 2>/dev/null | sort -rh | head -20To scan your entire Mac (requires administrator access), use:
sudo du -sh //* 2>/dev/null | sort -rh | head -30This can take several minutes on a large drive. The output is text-only — useful, but hard to navigate when you want to drill deeper.
Interactive drill-down with ncdu
If you have Homebrew installed, ncdu is a terminal-based disk usage browser with arrow-key navigation:
brew install ncdu
ncdu /Press Enter to drill into any directory and q to quit. It is one of the fastest ways to find what's filling your Mac disk when you are comfortable in the terminal.
Find What's Filling Your Mac Disk with a Visual Treemap
For most people, a graphical disk map is the clearest way to understand storage at a glance. A treemap represents every folder as a rectangle whose area is proportional to its size — large folders become large rectangles, so you can instantly see anomalies.
Crumb includes a Visualize mode that renders a whole-Mac treemap alongside a ranked list of your largest files and folders. Unlike the macOS Storage overview, it shows you the actual paths — including hidden system caches and application support directories — so you know exactly what you are looking at before you decide to remove anything.
To use it: open Crumb from the menu bar, switch to the Visualize tab, and let the scan finish. Click any rectangle to see its path, size, and last-modified date. From there you can decide whether to delete the item manually, open it in Finder, or hand it to Crumb's Uninstall flow (for apps) or one-click Clean (for caches and temp files).
What You Will Actually Find (and What's Safe to Delete)
Once you can see your storage breakdown, here is a practical guide to what each category means and how to treat it:
| Location | What lives there | Safe to delete? |
|---|---|---|
~/Library/Caches |
App-generated cache files (browsers, Xcode derived data, package managers) | Generally yes — apps rebuild caches on next launch |
~/Library/Application Support |
App databases, saved state, plugin data | Careful — removing the wrong subfolder deletes app settings or saved data permanently |
~/Downloads |
Everything you have ever downloaded | Yes, but review first — installers, documents, and media often live here |
/Library/Caches |
System-wide and shared app caches | Usually yes, but requires admin access; some caches are actively used |
/private/var/folders |
Temporary files macOS manages automatically | Let macOS manage this — manual deletion can cause unexpected behavior |
| Time Machine local snapshots | Hourly backups stored locally before syncing to your Time Machine drive | macOS reclaims these automatically when disk space is low; you can also delete them via tmutil deletelocalsnapshots / |
| iOS/iPadOS device backups | Full device backups made by Finder or iTunes | Yes, if you have newer backups or use iCloud backup instead |
A critical reminder: file deletion on macOS is permanent once you empty the Trash. If you are unsure what a folder does, do not delete it. Crumb's built-in AI explanation feature (the "Is this safe to delete?" button in Visualize) can analyze any path and explain what it contains and the risk level of removing it — which is particularly useful for the dozens of obscure subfolders that appear in ~/Library.
Step-by-Step: A Complete Storage Audit
- Check the overview first. System Settings → General → Storage. Note which categories are largest.
- Find your top 20 largest files. In Finder, sort your Home folder by size with "Calculate all sizes" enabled.
- Run a terminal scan for hidden folders. Use
du -sh ~//* 2>/dev/null | sort -rh | head -20to catch hidden directories Finder misses. - Get a visual overview. Open the Visualize tab in Crumb for an interactive treemap that covers your entire Mac, including system paths.
- Decide what to remove — carefully. Use the table above as a reference. Confirm before deleting anything in
Librarysubfolders you do not recognize. - Remove what you are confident about. Delete from Finder or use a cleanup tool for caches and logs. Empty the Trash only after you have reviewed its contents.
Conclusion
The biggest mistake people make when their Mac runs low on storage is deleting things blindly. Spending five minutes with the built-in storage overview, a Finder sort, or a disk visualizer will show you exactly where your gigabytes are going — and help you make confident decisions about what is worth removing. Diagnose first, clean second, and always keep a current backup before any major cleanup.