Part of: Mac storage full? Find what is using it and free up space safely (Storage full)
If your Mac fills up again soon after you free space, something is adding data steadily. The cause is almost always one of eight things, and checking them in order saves time compared with guessing.
First, take a snapshot of where you stand. Run df -h /System/Volumes/Data and note the Avail number. Check it again in a week. If it drops, one of these is the source.
1. Downloads
Browsers, mail and chat apps save files into Downloads, and nobody tidies it. Check it with du -sh ~/Downloads. See how to clean up the Downloads folder.
2. Old installers
Disk images and installers stay behind after you install an app. To find them, run find ~/Downloads -name "*.dmg". See how to delete DMG files.
3. iPhone and iPad backups
A backup can be many gigabytes, and new ones replace old ones only partly. See iPhone backups on your Mac.
4. Caches
Apps keep temporary data so they do not have to fetch it twice. Browsers, design tools and developer tools can grow large caches. Check with du -sh ~/Library/Caches. Most are safe to clear but not all, so read what is safe to delete in Library Caches.
5. Local snapshots
Snapshots can hold space that you thought you freed. Run tmutil listlocalsnapshots / to see them. macOS releases them when it needs room. Mac storage full but no files? explains this and the next cause.
6. Purgeable space and the Trash
Files in the Trash still use space until you empty it, and macOS can hold purgeable data for a while. If your free space never seems to match, read why moving files to the Trash does not free up space.
7. Mail, Messages and photos
Attachments and photos accumulate quietly. Check them with du -sh ~/Library/Mail ~/Library/Messages ~/Pictures. Terminal may need Full Disk Access to read some of these. Read Mail, Messages and the Photos library before you remove anything.
8. A growing app or developer tool
Some apps grow without telling you: chat apps, virtual machines, container tools and Xcode. In du -h -d 1 ~/Library | sort -h, look at Application Support and Containers. Developers can read how to clean up Xcode. Leftovers from deleted apps are covered in app leftovers on a Mac.
A simple way to find the cause
- Note
df -h /System/Volumes/Datatoday. - Run
du -sh ~/* | sort -hand keep the output. - In a week, run both again and compare. The folder that grew is your suspect.
You do not need special software for this. It is a small amount of work that tells you exactly where the space is going. For a wider look at what to check first, see what is taking up space on my Mac?.
Safe, Risky, Never
- Safe: emptying the Trash after a look, removing installers you already used, clearing files in Downloads you have checked.
- Risky: removing backups, caches you do not recognise, and large files you cannot name. Check first.
- Never: deleting system folders or the contents of your Photos library to gain space.
Why it feels like “no reason”
Most of these causes are slow. A cache grows a little each day. A backup replaces another only in part. A download is saved once and never opened again. Because each step is small, you never see the moment the space goes, and Storage settings only shows broad categories, so it does not name the folder that grew. That is why it feels as though nothing happened.
It also helps to remember that your own habits change. A new project, a longer video, a new app or a phone upgrade can each add several gigabytes in one go. If the trouble started at a particular time, ask what changed around then. The answer is often a single item, and removing or moving that one item can be enough.
Seeing it in one view
DiskJoy is our product. It scans the folders you allow and shows reclaimable space by category, which makes a regular check easier. A scan only reads file sizes and dates and changes nothing. DiskJoy is pre-alpha and cleanup is not available yet, so you remove things yourself. Download DiskJoy for Mac to try a scan.
If it still refills
If the disk keeps filling up and none of these matches, work through the complete guide to freeing up space on a Mac and look again at what changed in the last few weeks: a new app, a long download, a big project.
Frequently asked questions
Why does my Mac keep running out of space?
Something is adding data more quickly than you remove it. Common sources are iPhone backups, downloads, caches, snapshots, cloud sync, mail and messages, and developer tools.
Why is my Mac running out of space for no reason?
There is usually a reason you cannot see in Storage settings, because its categories are broad. A folder-by-folder look finds it.
How often should I check my Mac's storage?
Checking when you notice a drop, or every few months, is enough for most people. A quick look at the biggest folders costs less effort than a big cleanup later.