How to Clean Up Mac Storage: The Complete Guide

If your Mac is telling you storage is almost full, the instinct is to start deleting things: old downloads, a few photos, maybe that video project from last year. That usually buys you a gigabyte or two and nothing more, because the biggest offenders on most Macs aren’t in your Downloads folder. They’re in places Finder doesn’t show you by default, things like caches, logs, old iOS device backups, Time Machine local snapshots, and leftover files from apps you uninstalled months ago.

This guide walks through cleaning up Mac storage in the order that actually moves the needle, starting with finding out where the space went before you touch anything.

Step 1: Find out what’s actually using your storage

Apple’s own storage view ( menu → About This Mac → Storage → Manage) is a reasonable starting point, but it’s coarse. It groups huge amounts of disk usage into a bucket called “System Data” (sometimes labeled “Other”) that can run into double-digit gigabytes with no further breakdown. That’s not useful when you’re trying to decide what to remove. See what’s actually inside “System Data” for how to break it down properly.

What you actually want is a scan that shows real folders, real sizes, and lets you drill down. That’s the first thing OverClean does: point it at your disk (or a specific folder) and it builds a full picture of where your space went, sorted largest first, in 26 file categories instead of one opaque blob.

Once you can see the actual breakdown, cleanup stops being guesswork.

Step 2: Clear out caches first

Caches are temporary files apps and macOS itself create to speed things up. They’re designed to be deleted: the app or system just rebuilds what it needs the next time it runs. On a Mac that hasn’t been touched in a while, ~/Library/Caches alone can easily hold 5-15 GB across browsers, IDEs, Adobe apps, and Xcode if you do any development.

This is the single highest-value, lowest-risk step in any storage cleanup, which is why it gets its own detailed guide. The short version: don’t touch /System/Library/Caches by hand, do feel free to clear ~/Library/Caches entries for apps you recognize, and use a scanner that separates cache categories from personal files so you’re not eyeballing a raw file browser.

Step 3: Deal with old iOS backups and Time Machine snapshots

Two categories quietly account for a lot of “missing” space:

iOS device backups. If you’ve ever backed up an iPhone or iPad to your Mac via Finder or iTunes, those backups live in ~/Library/Application Support/MobileSync/Backup/ and don’t get cleaned up automatically. A few backups from old or upgraded devices can add up to 10-30 GB sitting there unused.

Local Time Machine snapshots. macOS keeps hourly local snapshots on your internal disk even without an external Time Machine drive connected, as a safety net. These are supposed to be thinned automatically when space runs low, but on Macs that are frequently near capacity, that automatic cleanup doesn’t always keep pace.

Both categories are things a general-purpose scan will surface but you’d rarely find by browsing Finder, since neither shows up as a normal folder you’d stumble into.

Step 4: Remove apps you don’t use, completely

Every app you’ve ever installed and uninstalled by dragging to the Trash left something behind: preferences in ~/Library/Preferences, cached data, support files, sometimes whole folders of user data the app never bothered to clean up after itself. Across a few years of installing and removing apps, “leftovers” like this commonly add up to several gigabytes of orphaned files with no app left to claim them.

Uninstalling properly, and finding what’s left over from apps you already removed, is worth doing right rather than by hand. We cover the full process in how to uninstall apps on Mac completely.

Step 5: Check developer and power-user clutter

If you write code, run Docker, or work with Xcode, this step alone can dwarf everything else. node_modules folders left behind by old projects, Python virtual environments you forgot about, Docker images and volumes, and Xcode’s DerivedData and simulator clones are notorious for silently consuming tens of gigabytes. None of it shows up when you sort your Documents folder by size, because it’s scattered across hidden directories like ~/Library/Developer and ~/.docker.

OverClean’s Development Tools scan and dedicated Xcode & Simulator Artifacts view exist specifically because this category is invisible to normal storage tools but enormous in practice. It’s not unusual for it to add up to 15-20+ GB on a Mac that’s had a few years of active development on it.

Step 6: Do a final pass with Applications and large files

Once caches, backups, and dev clutter are handled, look at what’s left: apps you installed once and never opened again, and individual large files (video exports, disk images, VM files) sitting in Downloads or Desktop. The Applications manager shows every installed app with its real size, including sizes Finder’s Get Info conveniently omits like embedded frameworks and support files, so you can sort by size and make quick decisions.

A note on safety

Every step above touches files, and touching the wrong file on macOS can break something. Don’t delete anything under /System, don’t delete files you don’t recognize inside ~/Library/Application Support for apps you still use, and be careful with anything flagged as “in use.” A tool with confirmation dialogs and Trash integration rather than instant permanent deletion is worth using for exactly this reason: it gives you a chance to notice a mistake before it’s unrecoverable.

Do this instead of doing it by hand

Everything above is possible manually with Finder, Terminal, and patience. It’s also slow, and it’s easy to miss the categories that actually matter. Most people who go looking for Downloads-folder clutter never find the 20 GB sitting in Xcode DerivedData or old iOS backups, because nothing points them there.

Download OverClean and run a free scan. The Dashboard and category overview are free, no account required. It’ll show you exactly where your space went in a few minutes, broken down by category instead of guesswork. If you want the deeper Applications, Leftovers, and Xcode/Simulator views on top of the free scan, see pricing.