Freeing up disk space on a Mac comes down to three things: seeing what’s using the room, clearing the files you no longer need, and emptying the places where deleted files wait. macOS has built-in tools for all three, and most of them live on one screen, so that’s where to start.
If your Mac just told you the disk is almost full, you don’t need to read all of this. Do the first two sections, empty your Trash, and you’ll likely have enough storage space again. If the storage space keeps disappearing, the later sections cover where it goes.
See what’s taking up space on your Mac
Your Mac keeps a running breakdown of its storage space.
- Open the Apple menu and choose System Settings.
- Click General in the sidebar, then click Storage.
- Wait a moment for the bar at the top to finish filling in. It shows the storage space used by each category and how much space is available.
On versions of macOS before Ventura, choose About This Mac from the Apple menu and click Storage instead. Everything else in this guide works the same on older versions of macOS, with slightly different menu names.
Some categories have a small i button next to them. Click it and you get a list of what’s inside, with a way to delete it. That’s especially useful for Applications, Documents, Messages, Trash, and TV.
One category confuses almost everyone: System Data. Apple describes it as the storage space used by every Apple and third-party file that doesn’t belong to a more specific category. Caches, logs, and temporary files live there. It isn’t something you clear by hand, and the next sections shrink it without you touching it directly.
Clear the easy wins first
These are safe, they’re quick, and together they’re usually the fastest way to clear up disk space on a personal Mac.
| Where | What’s in it | How to clear it |
|---|---|---|
| Downloads folder | Installers, zip files, and second copies of things you already saved | Open Finder, choose Go > Downloads, sort by size, delete what you’ve used |
| Trash | Everything you deleted | Deleted files keep their space until you empty your Trash |
| Old iPhone or iPad backups | If you back up your iPhone or iPad to your Mac, full copies of devices you may not own anymore | Delete them from the Storage screen or from Finder |
| Apps you don’t use | Apps, plus the files they downloaded | Delete from the Applications list on the Storage screen |
| Movies and music you can stream | Media already in the cloud | Delete the local copy, stream it when you want it |
| Junk and deleted mail | In Mail choose Mailbox > Erase Junk Mail, then Erase Deleted Items |
Start with the Downloads folder. It’s the one that grows without anybody deciding it should, and large files hide in it for years. Open Finder, go to Downloads, sort by size, open the biggest few, and delete the large files you no longer need.
Then empty your Trash. This is the step people skip, and it’s the reason a Mac still says its disk is almost full after an hour of deleting.
Let macOS optimize storage for you
The Storage screen also offers recommendations. They’re the built-in tools Apple gives you to optimize storage space, and each one is a setting you turn on once.
- Store in iCloud keeps your Desktop and Documents folders in iCloud Drive, your photos in iCloud Photos, and your messages in iCloud, with only recently opened files kept on the Mac when space is needed. It frees disk space on the Mac and uses your iCloud storage plan instead, which starts at 50 GB for $0.99 a month in the US. If your iCloud storage is already full, this one moves the problem more than it solves it.
- Optimize Storage removes Apple TV movies and shows you’ve already watched, and keeps only recent email attachments on the Mac when space is needed.
- Empty Trash automatically erases anything that has been in the Trash for more than 30 days. Turn on Empty Trash automatically and the most common reason for a full disk takes care of itself.
On top of those, macOS clears caches and logs that are safe to delete when space is needed, including interrupted downloads, staged updates, and Safari website data. That’s why System Data shrinks on its own when your disk gets tight.
Why is my Mac storage still full after deleting?
Deleted files don’t give their storage space back until they leave their holding areas. Three places to check:
- The Trash. Deleted files sit there, using space, until you empty it.
- Recently Deleted in the Photos app. Photos you delete wait there for 30 days. Open the Photos app, click Recently Deleted, and delete them for good if you’re sure.
- Caches macOS hasn’t cleared yet. The free number on the Storage screen can lag behind what you just deleted. Restart the Mac and look again.
If you need room for something big right now, like a macOS update, Apple suggests starting up in safe mode. Your Mac clears certain system caches while it’s in safe mode, and they rebuild later as needed. Restart normally when the update is done.
Where the space you can’t see is hiding
The Storage screen tells you what kind of files are using your disk space. It doesn’t tell you when two of them are the same file.
That’s where a lot of the room goes on a Mac that’s a few years old. The same folder copied to a backup drive twice. A camera card imported twice. An installer downloaded three times because you couldn’t find the first one. Each copy is a separate moment, so each one lands somewhere different, and the Storage screen counts every one of them in full. A 4 GB video saved in two folders uses 8 GB.
Two ways to find them:
- If the copies are photos inside the Photos app, the Photos app can find and merge them for you. How to find and delete duplicate photos on a Mac walks through it, along with a free Terminal command that lists identical files in any folder.
- For everything else, including files on an external hard drive, you need a duplicate file finder for Mac that compares what’s inside the files, since Finder only compares names, dates and sizes.
Moving files off the Mac counts too. Apple’s own advice is that if you have an external drive, you can move files to it, starting with large files such as photos and videos, including your whole Photos library. That frees the storage space on your Mac, as long as you keep the drive somewhere safe.
Using SupaDupa to find what’s filling a drive
SupaDupa is a Mac app for the part the Storage screen doesn’t cover: what’s inside your folders and your drives, and which of it is doubled.
Point it at a folder or an external hard drive. It reads everything and shows you what’s there by size and file type, including what’s been sitting untouched. Then it groups the files whose contents match, with the biggest recovery at the top.
What to expect:
- Finding and trashing exact duplicates is free, with no file limit.
- Copies go to the macOS Trash, so empty it afterward to get the disk space back.
- The oldest copy is kept by default, and every group keeps at least one file.
- It works on external hard drives, and search keeps working on a drive after you unplug it.
- It works on one connected folder at a time, so a full disk plus two drives is a few passes.
- There’s no undo button in the app for a trashed file. Restore from the Trash if you change your mind.
Leave the Photos library to the Photos app, and point SupaDupa at your folders, your downloads and your drives.
Pro is $49, once, and adds look-alike photos, tagging, and the organize planner. Freeing up disk space the way this guide describes is all in the free version.
Before you delete anything
- Back up first. Time Machine or a copy on another drive.
- Leave system folders alone. Don’t delete things inside the Library or System folders by hand to shrink System Data. macOS manages those.
- Sort by size before you start. Large files first means the biggest gains in disk space on your Mac for the least time.
- Empty the Trash at the end, then check the Storage screen again.
If the folders themselves are the problem, how to organize files on a Mac sets up a system that holds up after the cleanup.
Start with the Storage screen and the Downloads folder, then empty your Trash. That’s how most people clear up disk space on a Mac in under an hour. If you still need more space after that, go looking for the copies.