Quick answer
First check space in `Apple menu > System Settings > General > Storage`, then remove large files and duplicates, empty the Trash and browser cache, delete local Time Machine snapshots and leftovers from old apps. Do everything in small steps and with a backup so nothing important gets lost.
How to recognize the problem
- Mac shows a notification that the disk is almost full
- You cannot save a file or install a macOS update
- Apps are running slower and slower, and Storage shows a red bar
- Virtual memory and cache cannot expand, so the system stutters
Most common causes
Large and forgotten files
Videos, game installations, ISO files and old projects often take up tens of gigabytes, and they are buried deep in folders you rarely open.
Local Time Machine snapshots
When the backup disk is disconnected, macOS makes local snapshots on the internal disk and keeps them while there is space, so they can eat up a significant amount of space.
Cache and temporary files
Browsers, apps and system services pile up cache that is not deleted automatically, especially after months of use without cleaning.
Leftovers from deleted apps
Uninstalling by dragging to the Trash does not always remove data in `~/Library`, so folders with cache, logs and models remain.
Duplicates and old backups
Multiple copies of the same photos, projects or phone backups easily create several gigabytes of extra data.
Step-by-step fix
- 1
Find out where the space is going
Open
Apple menu > System Settings > General > Storage. Wait for it to calculate and look at the bar by category. Click on "Applications", "Documents" and similar to see the largest items. Do not immediately delete system categories you do not understand. - 2
Make a backup before cleaning
Before any deletion, connect an external disk and start Time Machine, or manually copy important folders to an external disk. If you do not have space for a full backup, copy at least Documents, Desktop and photos.
- 3
Empty the Trash and delete large files
Open Finder, choose
Go > Recentfrom the menu, or search by size in a folder. Drag files you do not need to the Trash, then empty it viaFinder > Empty Trash. Also check downloaded installers in theDownloadsfolder. - 4
Remove local Time Machine snapshots
Open Terminal and type
tmutil listlocalsnapshots /to see the list. Then runsudo tmutil deletelocalsnapshots <date>, where you replace<date>with a date from the list, orsudo tmutil deletelocalsnapshots /for all local snapshots; the administrator password will be required. This does not delete your files, only the local copies the system keeps on the disk, but you lose the ability to restore to those states. - 5
Clear browser and app cache
In Chrome, go to
Settings > Privacy and security > Clear browsing dataand delete the cache of images and files. In Safari, inSafari > Settings > Advanced, enable the Develop menu, then in theDevelopmenu choose the option to empty caches. For apps, use their own cache clearing options; do not delete folders manually if you are not sure. - 6
Remove leftovers from old apps
First delete the app from the
Applicationsfolder. Then in Finder pressShift + Cmd + G, type~/Libraryand review theApplication Support,CachesandLogsfolders. Delete only folders whose name clearly matches the removed app. - 7
Find duplicates and large media
In Finder, search by file type (for example
kind:movie) and sort by size. Photos and videos from iPhone can be moved to an external disk or to iCloud. Compare duplicates before deleting, preferably in small groups. - 8
Check Storage again
Go back to
System Settings > General > Storageand refresh the view. If it is still red, repeat the steps for the largest category. Manually deleting system folders or "optimizing" with tools of unknown origin is not recommended.
If there is still not enough space after cleaning
If the disk is still full, check whether macOS keeps a large update cache in System Settings > General > Storage and run the available recommendations there. Consider moving large libraries (photos, video projects, virtual machines) to an external SSD. If the Mac is older and the disk has been almost full for years, it may be time for a larger SSD or a new Mac, because macOS needs free space to work. Always save a copy first, then delete. If you do not know what is in a folder, do not delete it until you check.
How to prevent it
- Empty the Trash regularly and check the Downloads folder
- Leave at least 10 to 15 percent of disk space free
- Move large media to an external disk or to the cloud
- Delete apps together with their data in ~/Library
When to call a professional
If you cannot find what is taking up space, if the disk is system-damaged or if deleting does not help, it is better to contact IT support than to manually touch system folders.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
Does deleting local Time Machine snapshots remove my files?
No. Local snapshots are copies that macOS makes on the internal disk while the backup disk is disconnected. Deleting those snapshots does not touch the original files, but you lose the ability to restore to the state from that snapshot.
Can I safely delete the Caches folder in ~/Library?
You can delete the cache of individual apps, but not the whole folder at once. Apps will recreate the cache, and deleting everything can disrupt settings. Delete only folders whose name you recognize.
Why does Storage show less free space than Finder?
Storage also counts system and temporary files that Finder does not show, as well as local snapshots and cache. That is why the numbers differ; the figure in Storage after it is calculated is the relevant one.