How to free up disk space on a Mac

• Storage settings
• Trash
• Downloads
• Large files
• System Data
• iCloud
• Developer files
• Local snapshots
• Where Tidlark helps

1. Look at Storage settings

Open System Settings › General › Storage (you may need to scroll down in General). The path is the same on macOS 14, 15 and 26. The bar at the top shows what uses your disk, by category. It can take a minute to finish calculating.

Below it, macOS lists recommendations such as Store in iCloud, Optimize Storage (removes Apple TV films and shows you’ve already watched) and Empty Trash Automatically (deletes items that have been in the Trash for 30 days). Read each one before you turn it on. Apple explains each in Optimize storage space on your Mac, and Free up storage space on Mac lists more ideas.

Click the ⓘ button next to a category to see what’s inside. Documents is the most useful: it lists large files, your Downloads folder and unsupported apps, sorted by size, and you can delete from there.

2. Empty the Trash, and the other trashes

Items in the Trash still take up space. In Finder, choose Finder › Empty Trash, or press ⇧⌘⌫. Look through it first: emptying it can’t be undone.

Some apps keep their own bin. In Photos, check Recently Deleted; items there are removed after about 30 days. In Mail, empty the Trash and Junk mailboxes with Mailbox › Erase Deleted Items. External drives have their own hidden Trash folder, which empties when you empty the Trash while the drive is connected.

3. Go through Downloads

Downloads quietly collects installers, disk images and archives you already used. Open it in Finder, switch to list view (⌘2) and click the Size column to sort. Old .dmg, .pkg and .zip files of apps you’ve already installed are usually safe to remove.

Folders show “--” as their size in list view. To see folder sizes, choose View › Show View Options and turn on Calculate all sizes.

4. Find large files with Finder search

In Finder, press ⌘F and choose This Mac. Click the first criteria menu (it says Kind), choose Other…, tick File Size and click OK. Now set it to is greater than 1 GB. Finder lists every large file Spotlight knows about.

Videos, disk images, virtual machines and old backups usually top the list. Only delete what you recognise. Files inside an app’s folder in ~/Library belong to that app; remove those through the app itself, or see the uninstall guide.

5. Understand “System Data”

“System Data” is everything Storage settings can’t place in another category. It is not one thing you can delete. It typically includes:

• caches and logs kept by macOS and your apps;
• Time Machine local snapshots (see step 8);
• virtual memory swap files and the sleep image;
• app support data, such as mail databases, browser profiles and chat histories;
• developer files: Xcode simulators, device support files, Docker disk images.

Much of it is managed by macOS and shrinks on its own when space runs low. Don’t delete files in /System, /private/var or /Library by hand to make this number smaller. Restarting your Mac clears swap files and some temporary data, which is a safe first step if System Data looks unusually large.

6. Let iCloud keep the originals

If you use iCloud Drive, open System Settings › [your name] › iCloud › Drive and turn on Optimize Mac Storage (Apple’s steps). When space is low, macOS keeps older iCloud Drive files only in iCloud and downloads them again when you open them. You can also Control-click a file in iCloud Drive and choose Remove Download to free its local copy straight away.

For Photos, open Photos › Settings › iCloud and choose Optimize Mac Storage. Full-resolution originals stay in iCloud; your Mac keeps smaller versions.

Both need enough iCloud storage for everything you sync, and you need to be online to open files that aren’t downloaded.

7. Developer caches

If you write code, developer tools are often the biggest single source of reclaimable space:

• Xcode: DerivedData, old device support files and simulators can reach tens of gigabytes. See how to delete Xcode DerivedData safely.
• Homebrew: the first command shows old versions and downloads it would remove; the second removes them.

  brew cleanup --dry-run
  brew cleanup

• Docker: the first command shows disk use. The second removes stopped containers, unused networks, dangling images and build cache after asking you to confirm. Stopped containers you still need will be lost.

  docker system df
  docker system prune

• Local AI models: a single model can be 4 to 40 GB or more. See how to remove Ollama, LM Studio and Hugging Face models.

8. Time Machine local snapshots

If you back up with Time Machine, macOS also keeps local snapshots on your startup disk. They’re counted in System Data. macOS deletes them automatically after 24 hours, or sooner when it needs space, so usually you can leave them alone.

To see them, open Terminal and run:

tmutil listlocalsnapshots /

To ask macOS to thin them now, for example to reclaim up to 20 GB with the highest urgency:

tmutil thinlocalsnapshots / 20000000000 4

The amount is in bytes and the urgency is 1 to 4. To delete one snapshot by its date (the date part of its name, such as 2026-11-14-093012):

sudo tmutil deletelocalsnapshots 2026-11-14-093012

Where Tidlark helps

Everything above works without any extra app. Tidlark puts the same checks in one place and explains each item before anything is removed:

• a read-only Checkup, then System Junk, Large Files, Duplicates and a Storage Map of any folder;
• developer files and local AI models listed with what removing them costs;
• personal files are never pre-selected; your files go to the Trash and system items to a Holding Area you can restore from for 30 days;
• Maintenance can thin local snapshots and reclaim purgeable space, with a plain explanation of each task.

Tidlark won’t make a Mac with plenty of free space faster, and it doesn’t claim to. It is a one-time purchase of USD 56 for 2 Macs. See pricing or download Tidlark.