How to Free Up Storage on a Mac: 10 Ways That Work

If your Mac is telling you storage is almost full, the fastest fix is to open System Settings > General > Storage (or About This Mac > Storage on older versions of macOS) and work through Apple's own Recommendations panel first — Optimized Storage, iCloud offloading, and automatic Trash emptying typically recover the most space with the least risk. From there, a handful of targeted cleanups — iCloud Photos optimization, Time Machine snapshot management, Mail and Messages attachment caches, and the mysterious "System Data" category — usually close the gap, even on a Mac with a small SSD.

This guide walks through 10 ways to free up storage on a Mac, in the order Apple recommends trying them, plus what actually causes "System Data" or "Other" to balloon and what you can and can't do about it.

1. Check what's actually using your Mac's storage

Before deleting anything, see where the space is going. In macOS Ventura and later, choose Apple menu > System Settings, click General in the sidebar, then click Storage. On older versions, choose Apple menu > About This Mac, then click Storage. The pane shows a color-coded bar broken down by category — Applications, Documents, Mail, Messages, Photos, iCloud Drive, TV, Music, Podcasts, Trash, macOS, and System Data — and updates as you make changes.

According to Apple's own storage guide, each category has a specific meaning: Applications covers apps installed outside the system; Documents is everything in your home folder that doesn't fit another category (including unmanaged photos, PDFs, and Pages files); Mail and Messages include conversation history and attachments; and Trash holds anything you've deleted but not yet erased. Clicking into a category, or the Manage button, surfaces Apple's built-in Recommendations for freeing space, which is the logical next stop.

2. Turn on Optimized Storage and "Store in iCloud"

The Recommendations panel in Storage settings leads with the two options Apple considers the highest-impact: Store in iCloud and Optimize Storage. Store in iCloud turns on iCloud Drive and keeps your files, photos, and messages in iCloud while leaving only recently opened items in full on the Mac itself, downloading older files back on demand. Optimize Storage automatically removes Apple TV movies and TV shows you've already watched from local storage, since they can be streamed or re-downloaded later.

A third toggle, Empty Trash Automatically, erases anything that's been sitting in the Trash for more than 30 days, which prevents deleted files from quietly continuing to take up space. All three are reversible and are the options Apple itself recommends trying before manual cleanup — see Apple's storage settings guide for the full breakdown of each recommendation.

3. Offload your Photos library with Optimize Mac Storage

Photo and video libraries are usually one of the single biggest line items on a Mac's drive, and Apple has a dedicated setting for it. If you use iCloud Photos, open the Photos app, choose Photos > Settings > iCloud, make sure iCloud Photos is checked, then select Optimize Mac Storage. With this turned on, Photos keeps space-saving versions of your images on the Mac and stores full-resolution originals in iCloud, fetching the full-size file automatically if you open it to edit or export. Apple notes that an optimized library can take up less than 20% of the space of a fully downloaded one. If you need the originals back later — for example, before traveling without reliable internet — you can select Download Originals to this Mac at any time in the same settings pane, per Apple's Photos storage guide.

4. Understand why "System Data" or "Other" keeps growing

This is the category that sends most people searching for help in the first place — a Mac that reports 60, 100, or more gigabytes used by "System Data" with no obvious explanation. According to Apple's own description in its storage documentation, System Data "primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources," along with temporary files, fonts, app support files, and plug-ins that don't fit neatly into Applications, Documents, or any other named category.

The important detail, straight from Apple: you can't directly manage the contents of this category — it's handled entirely by macOS, and its size "varies in size depending on the current state of your Mac," per Apple's guide to finding and deleting files on Mac. In practice, System Data tends to swell right after a macOS update (while installer caches and old system files are still being cleaned up) and after heavy app installs, then shrinks again once free space runs low and macOS reclaims what it no longer needs. If the number looks abnormally large, the most effective lever isn't digging through System Data directly — it's working through the rest of the categories below (Mail, Messages, Trash, backups, unused apps, developer caches), restarting the Mac, and giving macOS time and free headroom to clean up on its own.

5. Don't worry about Time Machine's local snapshots — here's why

If you back up with Time Machine, your Mac also keeps local snapshots — point-in-time copies of your startup disk stored right on the internal drive — so you can restore files even when your Time Machine backup disk isn't connected. Apple's documentation is explicit that these don't behave like normal files for storage purposes: "Your Mac counts the space used by snapshots as available storage," and they don't compete with the space needed for downloading files, copying files, or installing software.

Time Machine saves a snapshot of your startup disk roughly every hour and keeps it for 24 hours, plus an additional snapshot of your last successful backup, and (since macOS High Sierra) one more before any macOS update is installed. Snapshots are deleted automatically as they age or as the system needs the space back, so in most cases there's nothing to manually clean up here — see Apple's local snapshots overview for details. If macOS is actively warning that storage is full, it will reclaim snapshot space itself before you need to intervene.

6. Clear out Mail and Messages attachment caches

Mail and Messages each get their own line in the Storage pane for a reason — attachments add up fast, especially in long-running threads with photos and documents. For Mail, Apple's guide recommends deleting large messages or ones with attachments, removing saved attachments while keeping the message text, and emptying the Trash mailbox via Mailbox > Erase Deleted Items. You can also set Mail to erase deleted messages automatically on a schedule in Mail's settings, so Trash doesn't silently accumulate — full steps are in Apple's Mail storage guide.

In Messages, you can delete individual messages, photos, videos, or files from a conversation by selecting them and pressing Delete, or remove every attachment of one type at once: click the contact or group name at the top of a conversation, scroll to a category like Photos, click Show more, then shift-click and delete the items you don't need. Deleted messages and attachments sit in a Recently Deleted folder for 30 days before they're permanently removed, so there's a safety net if you change your mind.

7. Empty the Trash, Downloads folder, and old device backups

A few low-risk, high-yield cleanups round out Apple's own recommended list. The Downloads folder is a common dumping ground for installers, PDFs, and files you only needed once — it's accessible from the Dock or via Finder's Go menu, and it's worth a periodic pass. Old local backups of a previous iPhone or iPad can also sit around taking up significant space long after the device itself has been upgraded or reset, and Apple specifically calls out removing them as a way to reclaim storage. Finally, make sure Trash is actually empty rather than just visually "deleted" — files you've removed still count against your free space until Trash is emptied, whether you do that manually or via the automatic 30-day Empty Trash setting covered above.

If you're mid-update and your Mac says there isn't enough free space to install it, Apple also notes that restarting in safe mode temporarily clears some system caches, which can free up just enough room for an update or large installer to proceed — though that effect reverses as soon as you restart normally, so it's a one-time unblock rather than a lasting fix. For the full official checklist these recommendations are drawn from, see Apple's guide to freeing up storage space on Mac.

8. Remove unused apps and clear developer caches

Apps you no longer use are an easy, obvious target — Applications gets its own category in Storage settings specifically so you can see how much room they're taking up collectively, and Apple's guidance is straightforward: delete or uninstall anything you don't use anymore. It's also worth checking for unused user accounts on a shared Mac, since each account's files, caches, and Library data count separately toward total storage used.

If you're a developer, Xcode deserves its own pass, since it's rarely counted by name in the Storage pane and instead shows up buried inside System Data or Documents. Xcode's DerivedData folder (at ~/Library/Developer/Xcode/DerivedData) stores per-project build artifacts that regenerate automatically the next time you build, so it's generally safe to clear out after quitting Xcode. Separately, device support files that accumulate every time you connect an iPhone or iPad for debugging — found at ~/Library/Developer/Xcode/iOS DeviceSupport and similar folders for other platforms — are never deleted automatically by Xcode, so on a machine used for active development these can quietly grow into tens of gigabytes over time and are worth reviewing periodically through Xcode's own Settings > Locations pane.

9. Which method frees the most space? A quick comparison

Not every method is worth the same amount of time. Here's roughly how the options above compare, based on what Apple's own documentation says each one targets:

10. What to do next

Start with the free, built-in tools: open Storage settings, work through Apple's Recommendations (Store in iCloud, Optimize Storage, Empty Trash Automatically), then turn on Optimize Mac Storage in Photos if you haven't already. Those steps alone resolve most "storage full" situations without deleting a single file yourself. If space is still tight, move through Mail and Messages attachments, clear your Downloads folder and old device backups, and uninstall apps you no longer use. Don't spend time chasing System Data directly — it isn't user-manageable, and it typically settles down once everything else is cleared and the Mac has been restarted. If you're also keeping macOS itself current, the latest macOS 27.0.1 update and the broader macOS 27 "Golden Gate" release both include their own under-the-hood storage and performance refinements worth knowing about. And if you split time between a Mac and a PC, the steps look different but the goal is the same — see our guide to freeing up disk space on Windows 11 for the equivalent walkthrough on that platform.

Written byFelix Moreau

Felix Moreau writes Pandromeda's software coverage and how-to guides. He covers Windows, macOS and Linux updates, the apps people rely on, emulators and developer tools, and turns official documentation into clear, numbered steps that work on the current version.

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