CleanLoupeTo free up space after a macOS update, delete any "Install macOS" app left in your Applications folder, remove installer files from Downloads, and give the Mac a day to finish re-indexing before you judge the storage numbers. Local Time Machine snapshots taken around the update can also hold space for a while; macOS removes them on its own, or you can delete them with tmutil. Then check System Settings for new background items the update or your apps added.
If you installed the yearly major update Apple ships each autumn in the last few weeks, this is a good time to do it. The update itself cleans up after itself, so you're mostly tidying the edges: files you downloaded, snapshots, and things apps re-added when they updated alongside it.
First: wait a day before judging storage
For the first hours after a big update, Spotlight re-indexes your disk and Photos re-analyzes your library. Both use CPU and both can change the storage figures while they work. A fan running and a System Data number that jumps around on day one are normal.
Leave the Mac on and plugged in for a while, let it finish, then look at Apple menu › System Settings › General › Storage. If you want to see whether Spotlight is still busy, run:
mdutil -s /
If search still misses files a few days later, rebuilding the index is the fix; see how to reindex Spotlight. Don't do that on day one, though, because you'd just restart the work it's already doing.
Delete the leftover macOS installer
If you downloaded the full installer from the App Store or Software Update, rather than updating in place, an app named "Install macOS" followed by the version name may still be in /Applications. It's large, and once the update is done you no longer need it.
In Finder, open Applications, find the installer app, and choose File › Move to Trash. Keep it only if you plan to make a bootable USB installer or update another Mac from it.
To check from Terminal whether one exists and how big it is:
ls -d /Applications/Install\ macOS*.app 2>/dev/null
du -sh /Applications/Install\ macOS*.app 2>/dev/null
No output means there's nothing to remove.
Clear installer files from Downloads
Updates often come with a round of app updates downloaded by hand: .dmg disk images, .pkg installers, sometimes .zip archives. Once the app is installed, the installer file is just a copy.
Open Downloads in Finder, switch to list view, and sort by Kind or by Date Added. Move old .dmg and .pkg files to the Trash. If you want to find them by size, press Command-F, set the Kind pop-up to Other › File Size, and use "is greater than". For the rest of the folder, see cleaning up the Downloads folder.
Check local Time Machine snapshots
If you use Time Machine, macOS keeps local snapshots on the internal disk, and some will date from around the update. They count toward used space and can make System Data look bigger than you expect. macOS keeps them about 24 hours and deletes them on its own when space is needed, so usually you can simply wait.
To see what's there:
tmutil listlocalsnapshots /
tmutil listlocalsnapshotdates /
If you need the space now, delete a specific snapshot by its date from that list:
sudo tmutil deletelocalsnapshots 2026-10-01-101500
Or ask macOS to thin snapshots until a given number of bytes is free, with an urgency from 1 to 4:
tmutil thinlocalsnapshots / 20000000000 4
Deleting local snapshots doesn't touch the backups on your Time Machine drive. You just lose the option to restore from that local copy.
If System Data is still large
System Data is a catch-all category, and System Settings gives it no ⓘ browse button, so you can't drill into it there. After an update it often shrinks again on its own once snapshots expire and indexing finishes. If it stays high, the usual causes are caches, logs, snapshots and app data. The longer walkthrough is in how to clear System Data on Mac, and if the Finder and Storage numbers disagree, purgeable space explained covers why.
A quick look at your own cache folder size:
du -sh ~/Library/Caches
Caches are normal and apps recreate them, so clearing them is a one-off space fix, not something an update requires.
Review new background items
Apps that update alongside macOS sometimes re-add helpers, and macOS may show "Background Items Added" notifications in the days after. Open System Settings › General › Login Items & Extensions. Check "Open at Login" and "Allow in the Background", and switch off anything you don't want. Names can shift between macOS versions, but the section has lived under General in both macOS 15 Sequoia and macOS 26 Tahoe.
If you see an entry for an app you deleted long ago, the launch agent file is probably still on disk. How to remove launch agents and login items shows where those files live and how to unload them.
Fix small glitches the update can leave
A couple of symptoms are common enough after a big update to mention:
- Duplicate apps in the Open With menu. Rebuild the Launch Services database:
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -r -domain local -domain system -domain user
killall Finder
- Blank Quick Look previews. Run
qlmanage -randqlmanage -r cache.
Only run these if you see the symptom. Otherwise, leave them alone.
How CleanLoupe does it
CleanLoupe is free, with no subscription, trial, ads or account, and it covers several of these steps.
Cleanup finds old installers (.dmg, .pkg, .mpkg, .xip, .iso) in Downloads older than 14 days and marks them Safe, and lists old archives in Downloads as Review. It also handles app caches in ~/Library/Caches (skipping caches that hold live state, such as iCloud and Find My), app logs, and old iOS update files. Items written in the last hour are never preselected, which matters right after an update when lots of files are fresh. Everything you remove goes to the Trash and into History, where Put Back restores it until you empty the Trash.
Performance can thin Time Machine local snapshots (your backup drive is unaffected), reindex Spotlight, rebuild Launch Services and reset Quick Look, using the macOS administrator prompt where needed. It also lists launch agents and daemons, so you can turn off or remove helpers that apps re-added, and it marks entries pointing at missing programs as Broken.
What it doesn't do: Cleanup doesn't look for the "Install macOS" app in Applications, so delete that one in Finder. It won't speed up the re-indexing macOS does after an update; that just needs time.
The Mac maintenance checklist puts this in context with the rest of the year's upkeep. To try the app, download CleanLoupe.
FAQ
Why is my Mac storage full after a macOS update?
Often it's temporary: local Time Machine snapshots from around the update, plus Spotlight and Photos re-indexing. macOS removes the snapshots on its own when it needs space. If it's still high after a few days, check for a leftover installer app and installer files in Downloads.
Can I delete the Install macOS app after updating?
Yes. Once the update is installed, the installer app in Applications isn't needed. Keep it only if you want to make a USB installer or update another Mac without downloading it again.
Why did System Data increase after the update?
System Data includes snapshots, caches and indexes, all of which change around an update. Give it a day or two. If it stays high, list local snapshots with tmutil listlocalsnapshots / and see whether any are still there.
Is my Mac slow after an update because of junk files?
Usually not. For the first hours after a big update the Mac re-indexes Spotlight and Photos, which uses CPU. Leave it plugged in for a while and it settles down. Deleting files won't make that work finish any faster.