"Your disk is almost full" is the moment people make their worst file decisions. Under pressure it is tempting to delete a big folder you don’t recognise, run a cleaner that promises gigabytes, or wipe caches you read about in a forum. Sometimes that works. Sometimes it removes a project, an app’s data or the only copy of a photo.

This guide takes the slower route: look first, remove the obviously disposable things, and keep an undo for every step. In most cases that recovers plenty of space without any risk.

Rule zero: have a backup, and use the Trash

Two habits make every step below safe:

Back up first. If you use Time Machine, make sure a recent backup finished. Cleaning up is exactly when you want a safety net.
Move to Trash, don’t delete immediately. Files in the Trash can be put back. Empty it a week or two later, once you are sure nothing is missing.

Be aware that some tools delete instantly. In System Settings ▸ General ▸ Storage, removing files from some categories deletes them immediately, and macOS warns that you can’t undo the action. Read those dialogs carefully.

Step 1: see what is actually using space

Open System Settings ▸ General ▸ Storage. The bar at the top shows space by category, and the list below lets you click the info button next to categories such as Applications, Documents or iOS Files to see their contents.

A few categories confuse people:

System Data includes caches, logs, local Time Machine snapshots and other files macOS manages. It often shrinks by itself when space is needed. Don’t go hunting inside it.
macOS is the operating system itself. You can’t and shouldn’t reduce it.
iOS Files are iPhone and iPad backups and software updates stored on your Mac. Old backups of devices you no longer own are often large and safe to delete here, if you are sure you don’t need them.

Step 2: use Apple’s built-in recommendations

The same Storage screen offers recommendations. Each is reasonable, but understand what it does first:

Recommendation	What it does	Watch out for
Store in iCloud	Keeps files, photos and messages in iCloud and only recent items locally when space is needed	Needs enough iCloud storage; older files download on demand
Optimize Storage	Removes Apple TV movies and shows you have watched, and keeps only recent email attachments locally	Downloads come back when you open them
Empty Trash Automatically	Erases items that have been in the Trash for more than 30 days	You lose the long undo window
Reduce Clutter	Opens Review Files to sort through documents and delete what you no longer need	Deletion here is immediate

Empty Trash Automatically is the same as Finder ▸ Settings ▸ Advanced ▸ Remove items from the Trash after 30 days. Thirty days is a sensible window for most people.

Step 3: start with Downloads

Downloads is where most reclaimable space hides, and it is also the folder with the least risk, because almost everything there exists somewhere else.

Open Downloads in Finder and choose View ▸ as List.
Choose View ▸ Show View Options and turn on Calculate all sizes, so folders show their size too.
Click the Size column to put the largest items at the top.

Then go through the categories that are almost always safe:

Installers you have already used. Disk images (.dmg), packages (.pkg) and zipped apps. Once the app is in Applications, the installer is just a copy you can download again.
Archives you have already unpacked. If photos.zip sits next to a photos folder, you probably need only one of them.
Duplicates. file (1).pdf next to file.pdf. Our guide to finding duplicate files covers how to confirm they are identical.

Move them to the Trash rather than deleting them outright.

Step 4: screenshots and screen recordings

Screenshots are small one by one and large in bulk; screen recordings are large from the start. By default macOS saves both to the Desktop.

List them all with a Smart Folder (File ▸ New Smart Folder, add a Raw Query rule with kMDItemIsScreenCapture == 1), or in Terminal with mdfind "kMDItemIsScreenCapture == 1".
Sort by date and review the old ones with Quick Look (Space).
Keep what you need, rename it to something meaningful, and trash the rest.

Step 5: large videos

Videos are usually the single biggest category in a home folder. In Finder, search for Kind is Movie, sort by size, and decide for each large file whether it belongs on an external drive or in a cloud archive rather than on your internal disk. Moving keepers off the Mac is often better than deleting them.

Step 6: apps you don’t use

Open the Applications folder in list view and look at Date Last Opened (add the column via View ▸ Show View Options if needed). Apps you haven’t opened in a year are candidates. Before removing one:

Check whether it has its own uninstaller; some apps, especially ones with system extensions, ship with one.
Remember that dragging an app to the Trash usually leaves its settings and data in ~/Library. That is often fine and is what lets you reinstall later without losing anything.

Never remove Apple’s built-in apps. Most can’t be deleted anyway, and they are part of the system.

What to leave alone

These are the usual sources of "I cleaned my Mac and now something is broken":

Anything inside ~/Library or /Library you don’t specifically understand, including Application Support, Containers and Group Containers. These hold app data, sometimes your only copy of it.
Caches, bulk-deleted. macOS and apps rebuild them, so deleting them gains space only temporarily and can make apps slower or misbehave until they recover.
Your Photos library package. Don’t open it in Finder and delete things inside it. Delete photos in Photos.
Local Time Machine snapshots. macOS removes them when it needs space. You can list them with tmutil listlocalsnapshots / if you are curious, but you rarely need to delete them by hand.
Files you don’t recognise in system locations. "I don’t know what this is" is a reason to look it up, not to delete it.

Making it a habit

A monthly ten-minute pass over Downloads, screenshots and the Trash prevents most "disk full" emergencies. Some people use an app to make that pass quicker.

If you’d like suggestions instead of digging through folders, Bowerbird, our Finder companion, has a Clean Up view that does the review in steps 3 to 6 for you. It suggests old installers in Downloads (including ones for apps you already have in Applications), screenshots older than 30 days, videos over 500 MB, large or long-untouched downloads, and apps you haven’t opened in 180 days, each with the reason it was suggested. Apple’s own apps are never suggested. Nothing is removed until you choose to (an optional automatic rule for old installers and screenshots is off by default), and when files are removed they go to the Trash, so you can put them back. It doesn’t touch caches or Library folders at all.

Whatever tool you use, the safe pattern is the same: look before you delete, start with obvious copies, and keep an undo until you are sure.

Bu konu Türkçe de var: Mac’te güvenli şekilde yer açma: yanlış dosyayı silmeden

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