# How to Free Up Disk Space on Mac: Measure, Then Delete URL: https://desktoptools.net/journal/how-to-free-up-disk-space-on-mac Type: blog Locale: en Published: 2026-11-06 Updated: 2026-11-06 --- > Measure your Mac's Storage first, clear the largest block, then handle System Data, developer caches and archives in the right order. Your Mac says the disk is full and you need room now. Open System Settings > General > Storage, read the bar, and clear the biggest category first. That one screen answers "how to free up disk space on Mac" for most people. The rest of this page is for when it does not. ## What is actually eating your disk? Guessing wastes an hour. Measure first. Open **System Settings > General > Storage** (Ventura 13 and later; older versions use Apple menu > About This Mac > Storage). Wait for the bar to finish calculating. It sorts the disk into Applications, Documents, Photos, System Data and a few others. ![Laptop screen showing a storage breakdown bar chart](https://fdzlnqpwsaniezitwiuw.supabase.co/storage/v1/object/public/cms-media/desktoptools/2026-11/c5d108-inline1.webp) Here is the rule that saves time: attack the largest block, not the easiest one. Deleting 300 MB of screenshots feels productive and changes nothing if Photos holds 90 GB. For anything the panel hides, use the terminal. This lists the size of every top-level folder in your home directory, smallest to largest: `# Sizes of everything in ~, sorted ascending. Last line is your biggest offender. du -sh ~/* ~/.[!.]* 2>/dev/null | sort -h | tail -15`It takes a minute on a busy disk. The output is blunt and it is accurate. Run it again one level down inside whatever folder wins. ## Which cleanup gives the biggest return per minute? Not all deletions are equal. Ranked by typical payoff for a working Mac, with the caveat that your disk will differ: - Old iPhone and iPad backups, Photos libraries and video files: often tens of GB each. - Developer leftovers (Xcode, simulators, Docker, package caches): easily 20 GB or more if you build software. - Apps you installed once and forgot. - The Downloads folder: installers, disk images, zip files you already unpacked. - Caches and logs: real, but small compared to the first four and they regrow. Apple's own [support page on freeing up storage](https://support.apple.com/en-us/102624) lists the same culprits: Downloads, unused apps, old device backups, Mail junk, and media you can stream again. Nothing exotic. The skill is doing them in the right order. ## Is "System Data" safe to delete? Skip the panic. System Data is the catch-all bucket for files that do not fit another category, and Apple notes it was labeled "Other" in older macOS versions. It is not one folder you can drag to the Trash. What usually lives there: caches, logs, local Time Machine snapshots, leftovers from apps you removed, and cached iOS backups. Some of that macOS clears on its own when it needs room. Some you must clear yourself. If System Data looks absurd (say 80 GB on a 256 GB machine), check two things before anything else. Local snapshots first: `# List local Time Machine snapshots on the boot volume tmutil listlocalsnapshots /`Each line is a snapshot macOS keeps so Time Machine can restore files while the backup drive is away. They normally thin out by themselves. If one is stuck, `tmutil deletelocalsnapshots ` removes it, using the date string from the listing. Do not delete snapshots in bulk if your external backup is behind. That snapshot may be your only recent restore point. Second: restart the Mac. This is dull advice and it works more often than it should. A reboot clears temporary files and prompts macOS to release space it had marked as reclaimable. ## Why does free space not match what you deleted? You emptied the Trash, the number barely moved. Two reasons. Items in the Trash do not free space until you empty it. Apple says so directly. And some space shown as used is "purgeable": macOS can reclaim it on demand, so it counts as available when you save a big file, but it may not read as free in a quick glance. The OS decides when to purge, not you. ![Pile of old installers, folders and hard drives beside an empty box](https://fdzlnqpwsaniezitwiuw.supabase.co/storage/v1/object/public/cms-media/desktoptools/2026-11/b46fde-inline2.webp) Practical test: if you need space for one specific job (a 30 GB OS update, a video export), do not trust the vague total. Delete until Finder's Get Info on the disk reports the free space you need, then retry. If the number still lags, restart and check again. ## What to delete by hand, in order If you have 20 minutes, go through this list top to bottom. Each step is reversible until you empty the Trash. **Downloads.** Open it from Finder with Go > Downloads and sort by size. Disk images (`.dmg`), installers and zip archives you already used are dead weight. Nine times out of ten this folder is bigger than you think. **Apps you no longer open.** Applications in the Storage panel sorts by size. Drag the unused ones to the Trash. Some apps leave support files in `~/Library/Application Support`. Check there only for apps that were large. **Device backups.** Old iPhone and iPad backups sit in `~/Library/Application Support/MobileSync/Backup`. Each can reach many GB. If you have a current iCloud or external backup, delete the stale ones from Finder rather than hand-deleting the folders. **Mail.** In Mail, choose Mailbox > Erase Junk Mail, then Mailbox > Erase Deleted Items. Large attachments in old threads add up for heavy email users. **Photos and video.** Photos libraries often win the "biggest block" contest. Move the whole library to an external drive, or keep originals in iCloud and let the Mac hold optimized versions. iCloud storage starts at 50 GB for $0.99 a month according to Apple, which is cheaper than a larger internal SSD. ## What developers should clear first If you build software, your Mac fills up in a different way. The usual suspects are all regenerated on demand, which makes them safe targets. `# Xcode build products and indexes. Rebuilt on next compile. rm -rf ~/Library/Developer/Xcode/DerivedData # Simulator runtimes you no longer have an SDK for xcrun simctl delete unavailable # Homebrew: old versions and download cache brew cleanup # Docker: unused images, stopped containers, dangling volumes (read the prompt) docker system prune`DerivedData is the one that surprises people. It grows silently with every project you open. Deleting it costs you one slow rebuild and returns the space immediately. Docker is the dangerous one: `docker system prune` removes stopped containers and unused networks and images, so read what it lists before you confirm. Node projects carry the same pattern. Every abandoned repo with a `node_modules` folder keeps hundreds of MB. Find them in one pass, then decide: `# Find node_modules folders, show sizes, biggest last find ~/code -name node_modules -type d -prune -exec du -sh {} + 2>/dev/null | sort -h | tail -10`Change `~/code` to wherever your projects live. Delete the ones from projects you are done with. `npm install` brings them back if you are wrong. ## Do you need a cleaner app? Honest answer: probably not for the first 10 GB. Everything above uses built-in tools and costs nothing. A cleaner earns its place when you do this often, when you manage several Macs, or when you want a visual map of the disk instead of a `du` listing. Setapp is the pragmatic route if you want to try that category without committing to a single license. It is a subscription bundle, so the usual trade-off applies: you rent access to a catalog instead of owning one binary. Skip any app that wants to run in the background all day, asks for Full Disk Access without explaining why, or promises to "optimize" your Mac. A disk cleaner should run, show you a list, let you uncheck things, then quit. One tool. One job. If you already use a launcher, it can shorten the loop. You can jump straight to a folder, reveal it in Finder, and sort by size without clicking through four windows. Alfred is a one-time purchase if you dislike subscriptions. Raycast covers similar ground with a free tier, if you prefer that model and are fine with its account-based setup. Neither of these deletes anything for you. They just shorten the walk to the folders you need to inspect. ## When an external drive beats deleting Some data is not junk. A 4K video archive, a music production library, a decade of photos. Deleting it is the wrong move. Move it. ![External SSD plugged into the side of a laptop](https://fdzlnqpwsaniezitwiuw.supabase.co/storage/v1/object/public/cms-media/desktoptools/2026-11/0cc1b7-inline3.webp) A portable SSD is the cleanest answer: fast enough to edit from, small enough to forget about. Keep the projects you touch this month on the internal disk and park the rest. Whatever you move, keep a second copy somewhere. A single external drive is an archive only until it fails. If the internal disk is small and you buy into the Apple ecosystem anyway, count the cost both ways. A year of iCloud at the 50 GB tier is a few dollars. A year of fighting a full disk costs more in lost hours. ## How to keep it from filling up again Cleanup is a one-off. Prevention is a habit, and it takes three small changes. Turn on the Storage recommendations that apply to you, including emptying the Trash automatically after 30 days. Set a recurring calendar reminder to clear Downloads once a month. And when a disk crosses 85% full, treat it as a warning, not a target. macOS performs worse as the disk fills, because it needs room for swap files and temporary data. That is the whole routine. Measure in Storage, clear the biggest block, check snapshots and caches only if System Data is huge, and move big archives off the machine. If your free space is still stuck after that, restart once and look again. ## FAQ ### How do I check what is using space on my Mac? Open System Settings > General > Storage on macOS Ventura 13 or later. On older versions, use Apple menu > About This Mac > Storage. For hidden folders, run du -sh ~/* | sort -h in Terminal to list the biggest items. ### Is it safe to delete System Data on a Mac? System Data is a catch-all category, not one folder. Do not delete it wholesale. Clear Trash, restart, and check local Time Machine snapshots with tmutil listlocalsnapshots /. macOS removes much of the rest on its own. ### Why does my Mac still show little free space after I empty the Trash? Some space is purgeable, meaning macOS can reclaim it on demand but may not report it as free. Restart the Mac and check again. If you need space for a specific job, delete until Get Info on the disk shows what you need. ### Do I need a Mac cleaner app? Not for the first 10 GB. Built-in tools and a few Terminal commands cover Downloads, backups, caches and developer leftovers. A cleaner helps if you do this often or want a visual map of the disk. ### Is it safe to delete Xcode DerivedData? Yes. DerivedData holds build products and indexes that Xcode regenerates on the next build. You pay with one slower compile and get the space back immediately. ### Should I move files to iCloud or an external drive? Both work. iCloud starts at 50 GB for $0.99 a month according to Apple and keeps files reachable. A portable SSD suits large archives you rarely touch. Keep a second copy of anything you move.