"Junk files" on a Mac: what they really are and which to remove

"Junk files" on a Mac is a label, not a kind of file, and macOS itself never uses it. Cleaner apps put it on a mixed group: app caches, logs and crash reports, language files inside apps, leftovers of apps you've removed, installers, old device backups and duplicates.

Only part of that group deserves removal. Installers you've already used, caches of apps you've removed, caches that have grown far past the rest, old logs and crash reports, and iPhone software update files can all go. Leftovers of removed apps can too, once you've checked they hold nothing of yours.

The rest is either a poor trade or not something to judge in bulk. Language files and other parts inside apps save little and can stop an app from opening. Preferences are tiny. Temporary files, swap and snapshots belong to macOS. Backups, document versions and some duplicates may be the only copy you have.

None of it makes a Mac faster. Clearing caches frees space until apps rebuild them, and that's all. The sections below take each kind of "junk" in turn: what it is, what removing it costs, and how to remove it in Finder or in the app that owns it.

What "junk files" on a Mac really means

The word suggests that everything under it is waste. That's the part to question. Each item in a "junk" total has an owner, a reason to exist and a cost to remove, and those differ a lot from one item to the next.

Where does the word come from?

Apple's support pages don't use it. When Apple describes what macOS removes by itself, it talks about caches and logs that are safe to delete, and names temporary database files, interrupted downloads, staged macOS and app updates, and Safari's website data.

"Junk" comes from cleaner apps, where it names a category in a scan result. A category with that name invites one click for the whole lot. That's where cleanup tends to go wrong: one click for a group that mixes the harmless with the irreplaceable.

What does a cleaner app count as junk?

CleanMyMac is a well-known example, and its help pages say exactly what it groups as System Junk. There are twelve groups: user and system cache files, user and system log files, language files, universal binaries, document versions, iOS device backups, broken preferences, broken login items, folders of deleted users, and Xcode junk.

It handles the riskier groups with some care, and its help pages say so. It doesn't select the most recent iOS backup by itself, never offers a document's earliest or latest version, and leaves Xcode's archives and module caches unselected. It also notes that deleted users' folders aren't necessarily waste.

Other cleaners use similar groups under their own names. As a map of where space goes, the groups are useful. The single word on top of them is what hides the differences.

Four kinds of "junk"

Everything in those groups falls into one of four kinds. The kind tells you what to do; the label doesn't.

• It comes back by itself. Caches, logs and crash reports are made again by whatever made them. Removing them costs time, never data.
• You can get it again. Installers, update files and apps can be downloaded again, if you know where from.
• It may be the only copy. Backups, document versions, a deleted user's folder and an app's data folder may exist nowhere else.
• Something else manages it. Temporary files, swap and snapshots belong to macOS, and app bundles to their developers.

What cleaners call junk	What it really is	Comes back by itself?	Worth removing?
App caches	Data apps can rebuild	Yes	Removed apps' caches and outliers
Logs and crash reports	Records for troubleshooting	New ones, yes	Old ones, when nothing's wrong
Language files, universal binaries	Parts of signed apps	Only with an update	No
Leftovers of removed apps	Caches, data, settings	No	Caches and logs; data after a look
Installers and update files	Downloads you've used	Download again	Yes, once installed
Broken preferences and login items	Settings and startup entries	No	Little space to gain
Backups and document versions	Possibly the only copy	No	Only after checking
Temporary files	macOS's working files	Yes	Leave them to macOS

Caches: the largest part, and the part that grows back

Caches are usually the biggest group in any scan. Apps and macOS services keep them so they can load things faster. Most live in ~/Library/Caches, in a folder named after the app or its bundle ID, and sandboxed apps keep their own inside their containers.

Is it safe to delete cache files on a Mac?

Yes, for the caches in your own Library folder. Apple's guidelines for developers say an app should keep only data it can recreate there. Remove a cache and the app builds it again, more slowly at first, and some apps download data again.

The catalog behind this site rates App caches as Safe, and the same goes for caches inside sandboxed apps' containers. The cost is a slower first launch or page load, not lost work.

Quit an app before you remove its cache folder. An app that's running may still be using the files, and it can recreate them as soon as they're gone. Move the folder inside Caches to the Trash, never the Caches folder itself.

Why is clearing caches only a one-off gain?

Caches grow back as you use your apps. That's what they're for. A browser fills its cache again as you browse, and other apps rebuild theirs as you use them.

macOS also clears caches it knows are safe to delete when space runs low. So a large cache on a Mac with plenty of free space isn't a problem waiting to be fixed. It's an app working as designed, and clearing it on a schedule just makes the app do the same work again.

Which caches are worth clearing?

Three kinds of cache earn the effort:

• Caches of apps you've removed. Nothing will use them again, and nothing removes them.
• A cache far larger than the rest, such as a browser's or a video editor's. Clear it in the app's own settings where it has one.
• Update downloads apps left behind. Apps that update themselves with Sparkle, or with Squirrel like many apps built with Electron, keep downloaded updates in their cache folders.

Sparkle removes downloads older than 10 days on its own, but a recent one can take hundreds of megabytes. Squirrel's folders end in .ShipIt, such as com.example.app.ShipIt, and an update that hasn't been installed yet can take several hundred megabytes. Both are Safe: the app downloads an update again if it needs one.

Which caches need more care?

/Library/Caches, at the top of the disk, holds caches shared by every user of the Mac. Most items there belong to the system, so moving them needs an administrator password, and a service may only rebuild its cache after a restart. That makes them Usually safe: usually safe, at a cost to know about.

Browser caches are best cleared from the browser. Safari, Chrome and Firefox keep their cache apart from cookies and website data, and their own menus and settings can clear one without the other. Removing website data can sign you out of sites; clearing the cache alone doesn't.

Logs, crash reports and diagnostic files

Logs are what apps and macOS write down as they work, so someone can work out later what went wrong. Crash reports are what macOS saves when an app crashes, hangs or uses a lot of resources. Both turn up in every "junk" total, and both are usually small.

How much space do logs really take?

Across a whole Mac, logs and crash reports typically add up to somewhere between a hundred megabytes and a few gigabytes. Many Macs have far less.

The exception is a log that an app or tool keeps writing without limit, such as a helper stuck repeating the same error. One file like that can grow to many gigabytes. Open ~/Library/Logs in Finder, choose View › as List, and sort by size to find it.

Which logs can you remove?

Where	What it holds	Level	How to remove it
~/Library/Logs	Logs your apps write	Safe	Move the contents to the Trash, keep the folders
~/Library/Logs/DiagnosticReports	Crash, hang and diagnostic reports	Safe	In Console, or in Finder
/Library/Logs	Logs of helper tools and installers	Usually safe	Needs an administrator password
/private/var/log	Text logs macOS rotates	Managed by macOS	Leave it
/private/var/db/diagnostics	The unified log	Managed by macOS	Leave it

Leave the log folders themselves in place. Some programs, including background jobs, expect them to exist.

How do you delete crash reports?

Open Console, in Applications › Utilities. Under Reports in the sidebar, choose Crash Reports, Spin Reports, Log Reports or Diagnostic Reports, then select a report and choose File › Move to Trash.

You can also open the DiagnosticReports folder in Finder and move reports to the Trash there. Their names end in .ips for crash reports, .spin for spin reports and .diag for diagnostic reports.

When should you keep logs?

When something is wrong. If an app keeps crashing or your Mac restarts by itself, the logs and reports are the evidence a developer or Apple Support may ask for. Keep them until the problem is fixed, or until you've sent them.

The rest of the time, old logs help nobody. Nothing on your Mac needs them to work, and apps start new ones as they run.

Language files and universal binaries: the "junk" inside apps

Two groups in some cleaners aren't separate files at all. They're parts of the apps you use, and removing them means changing those apps.

What are language files on a Mac?

Mac apps carry their translations inside them. In an app's package, each language has a folder whose name ends in .lproj, such as en.lproj or de.lproj, with the app's text and sometimes its images in that language. macOS shows the one that matches your language settings.

Removing the languages you don't read is old cleanup advice, and it's still offered. Today it's a poor trade.

Is it safe to remove language files?

Not really. Removing files from inside an app changes it, and macOS checks that apps haven't been altered. Apple says that when macOS detects software has been modified or damaged, it tells you the app can't be opened.

Even when an app still opens, the space usually comes back with its next update, which installs a complete new copy of the app, translations included. So the gain lasts until the next update, and the risk is an app that won't start.

Apple's own apps can't be trimmed at all. Since macOS Catalina, macOS has lived on a read-only system volume, which protects the apps that are part of it from changes.

What about universal binaries?

Many Mac apps are universal: one app containing code for both Apple silicon and Intel Macs, so it runs natively on either. On an Apple silicon Mac, the Intel part goes unused, so some tools offer to strip it out.

It has the same two problems as language files. It changes a signed app, and CleanMyMac's own help notes that the removed part can come back after an update. You also lose the ability to copy that app to an Intel Mac and run it.

What to do instead

If an app is large, the useful question is whether you use it. Removing the whole app, with its uninstaller if it has one or by dragging it to the Trash, frees all of its space at once. You can download it again if you change your mind.

Leftovers, broken preferences and login items

When you drag an app to the Trash, only the app goes. Its caches, logs, data folder, container, settings and login items stay behind, mostly in your Library folder, sometimes for years. Cleaners group these as leftovers, broken preferences and broken login items.

What do apps leave behind when you delete them?

Leftovers come in two kinds, and they need different decisions:

• Caches and logs. Safe to remove. Nothing uses them once the app is gone.
• Application Support folders and containers. These hold the files an app manages for you, and they can include your own work: a library, a chat history, projects saved only inside the app.

That's why Application Support folders are Review first. Open the folder before you remove it. If it holds something you'd want if you reinstalled the app, copy it somewhere first.

Most leftovers are small. Some apps leave gigabytes behind, usually in their data folder.

Are broken preferences worth deleting?

A preference file holds an app's settings, as a small file in ~/Library/Preferences. A cleaner calls one broken when it finds it damaged. Removing it frees almost nothing, and the app goes back to its default settings.

If an app misbehaves, resetting its settings is a troubleshooting step for that one app, not a way to free space. Leave preferences out of storage cleanups altogether. The same goes for Saved Application State, which only remembers an app's windows.

What are broken login items?

Login items are apps and helpers that open when you log in. A broken one points to an app that's no longer there, and macOS marks it with a warning symbol because it was moved or deleted. Login items take almost no space, but they're worth tidying.

Open System Settings › General › Login Items & Extensions. Under Open at Login, select an item that belongs to an app you've removed and click the Remove button. Under App Background Activity, which lets apps run tasks while they aren't open, turn off entries for apps you no longer have.

In macOS Sonoma and earlier, the pane is called Login Items.

What about folders from deleted user accounts?

When an administrator deletes a user and chooses Save the home folder in a disk image, the image goes into /Users/Deleted Users. It can be large, and it may be that person's only copy of their files.

Open the disk image and look, or ask the person, before moving it to the Trash. If you're deleting an account yourself and nobody needs its files, Delete the home folder frees the space at once. Both options appear in System Settings › Users & Groups when you click the information button next to the user, then Delete User.

Installers, downloads and update files

These are the easiest wins in any "junk" list, because they're downloads you've finished with. The only question is whether you could get each one again.

Can you delete .dmg and .pkg files after installing?

Usually, yes. Apps from the web arrive as a disk image (.dmg) or an installer package (.pkg) in your Downloads folder. Once the app is installed, it runs from Applications and doesn't need the file.

Keep the ones you couldn't download again, such as a paid app's installer from a developer that has gone. A disk image can also hold your own files rather than an app, so open it before you decide. Archives you've already opened, such as .zip files, are the same: check that the extracted copy is there first.

Old macOS installers

An app such as Install macOS Tahoe in your Applications folder is a full macOS installer you downloaded and didn't run. It takes many gigabytes. You only need it to install that version again or to make a bootable installer, and Apple lets you download installers again for versions your Mac supports.

iPhone and iPad software update files

When you update or restore an iPhone or iPad from Finder, macOS keeps the device's software, several gigabytes per file. These are Safe: if Finder needs the software again, it downloads the current version from Apple.

Open System Settings › General › Storage and click the information button next to iOS Files. It lists backups and software files; select an update file and click Delete.

Mail Downloads

When you open an attachment in Mail, Mail saves a copy in a Mail Downloads folder so another app can open it. By default, Mail deletes the copy when you delete the message. Copies from messages you keep stay, and so do copies you edited.

The originals stay in your messages, so unedited copies are no loss. An edited copy may be the only one with your changes, so check before removing the folder. To choose when Mail removes these copies, open Mail › Settings, click General, and change Remove unedited downloads.

Item	Where it is	Level	Check before removing
Disk images and installer packages	~/Downloads	Review first	You can download it again
Archives you've opened	~/Downloads	Review first	The extracted copy is there
macOS installers	/Applications	Usually safe	You don't need that version offline
iPhone and iPad software files	~/Library/iTunes	Safe	Nothing
App update downloads	~/Library/Caches	Safe	Nothing
Mail Downloads	Mail's container	Usually safe	No edited attachments inside

Duplicates, backups and document versions

The groups in this section are where "junk" totals go most wrong. Each item may be the only copy of something, and some don't free the space they appear to take.

Are duplicate files junk?

A true duplicate wastes space. But on APFS, the format every current Mac uses for its startup disk, many copies aren't real copies. Apple describes a clone as a copy of a file that occupies no additional space on disk. Copies made on the same disk with Finder are usually clones.

The two files share their data until one of them changes. Finder still shows each clone at its full size, so a folder of clones looks large. Delete a clone and you get back almost nothing, because the data still belongs to the other file.

Howard Oakley of The Eclectic Light Company tested this by cloning a large file several times: used space didn't change, and removing the clones gave nothing back. Copies on another disk, or files saved separately, are real duplicates and free their full size.

Before removing a duplicate, decide which copy to keep: the one in the folder you use, with the name your other files and apps point to.

What about duplicate photos?

Use Photos itself, never Finder. Open Photos and click Duplicates below Utilities in the sidebar. Select the duplicates and click Merge. Photos keeps one copy and moves the rest to Recently Deleted, where you can recover them for 30 days.

Old iPhone and iPad backups

A backup of each device you've backed up to this Mac can take tens of gigabytes. Backups of devices you've sold, and copies you archived before an update, stay until you delete them.

They're Review first because a backup may be the device's only one. An encrypted backup also holds saved passwords, Wi-Fi settings and Health data. Check that the device backs up to iCloud first, then delete old backups from iOS Files in Storage settings, or with Manage Backups in the device's Finder window.

Document versions

Many apps save versions of your documents automatically as you work, and macOS keeps the earlier ones in a hidden folder at the top of the disk. They're your documents' history, not waste, and only macOS changes that folder.

To remove one, open the document, choose File › Revert To › Browse All Versions, and select the version. Move the pointer to the top of the screen, then choose File › Revert To › Delete This Version. Removed versions can't be recovered, and they aren't in your Time Machine backups.

Is the Trash junk?

Some scans count it. It's the opposite: the Trash is where you can still change your mind, and emptying it is permanent. Look through it before you empty it. If you'd rather not think about it, turn on Remove items from the Trash after 30 days in Finder › Settings › Advanced.

Why "junk" totals look bigger than the space you get back

A scan that finds tens of gigabytes of "junk" can free much less in practice, without anything going wrong. Five things inflate the figure, and none of them needs bad faith.

Space macOS would free anyway

macOS clears caches and logs that are safe to delete when space is needed, and Finder already counts purgeable space, such as Time Machine's local snapshots, as available. A total that adds those up offers you space that was, in effect, already yours.

Copies counted twice

Clones share their data, and a hard link is a second name for the same file. A tool that adds up file sizes counts that data twice, even though removing one copy frees little or nothing.

Size on paper, not on disk

APFS stores sparse files, keeping only the parts that have actually been written. A disk image or a virtual machine's disk can report a size far larger than the space it takes. Removing one frees what it takes, not what it reports.

Space that comes straight back

Caches grow back with use. A total measured after a week of use can be found again a week later. The space is real, but you only borrow it.

Item counts aren't sizes

Some scans lead with how many items they found. Thousands of small cache and log files can add up to a few hundred megabytes. The figure that matters is bytes, and which of those bytes stay gone.

What's in the total	Why it overstates	What you really get back
Caches macOS would clear itself	macOS frees them when space is needed	Space a little sooner
Clones and hard links	Shared data is counted twice	Little or nothing
Sparse disk images	Reported size exceeds real size	The real size only
Caches you use daily	They grow back	Space for a few days
Many tiny files	Counted by number, not size	Whatever they weigh, often little

• App caches2–30 GB · Safe
• Shared caches in /Library1–10 GB · Usually safe
• Logs and crash reports0.1–5 GB · Safe
• Squirrel update leftovers0.2–3 GB · Safe
• iPhone software update file, each5–15 GB · Safe
• Leftovers of one removed app0.1–15 GB · Review first
• Duplicates1–50 GB · Review first
• Downloads and large old files5–100 GB · Review first

Typical ranges on Macs that have these items at all, from the research behind the app's catalog. Many Macs have far less. Duplicates on APFS often free less than their size, because copies on the same disk can be clones.

Does removing junk files speed up a Mac?

No, and it's worth being plain about, because the promise of a faster Mac often travels with cleanup advice.

What does clearing caches do to speed?

Caches exist to make apps faster. Clear them and apps are slower for a while, as they rebuild what they lost. Logs, installers and language files sitting on the disk don't slow anything down either; a file that nothing opens costs nothing but space.

When does free space matter?

Apple's checklist for a slow Mac starts with the startup disk, which may not have enough free space. Its other steps are about memory, quitting apps you're not using, apps your Mac doesn't support, and repairing the disk. Clearing caches isn't on it.

So if your disk is nearly full, making room helps your Mac work normally, and it lets updates and large copies finish. The biggest room usually comes from your own large files, old backups and apps you don't use, not from caches.

Whether you need a tool for this at all is a fair question. The post Do you need a Mac cleaner app? compares what macOS already does with what tools add.

How to clear what's worth clearing, without a cleaner app

Everything worth removing from a "junk" list can be removed with what's built into macOS. It takes longer than one button, and in exchange you see each thing before it goes.

A careful pass, step by step

1. Open System Settings › General › Storage, let the numbers settle, and note the largest categories.
2. Click the information button next to Documents, then the button for downloads. Sort by size, and move installers and archives you've finished with to the Trash.
3. Click the information button next to iOS Files. Delete software update files, and backups of devices you no longer own.
4. Quit your apps. In Finder, choose Go › Go to Folder, enter ~/Library/Caches, and move the folders of apps you've removed, and any outsized cache, to the Trash.
5. Open Console and move old reports to the Trash, if nothing on your Mac is misbehaving.
6. Open Login Items & Extensions and remove entries for apps that are gone.
7. Open the apps you use, check they work, then empty the Trash.

What a careful pass usually finds

On most Macs, a pass like this finds a few things that matter and a lot that doesn't. The large items are often downloads, old backups and one or two oversized caches. The long tail of small caches, logs and leftovers adds up to far less.

That's also why the order above starts with Storage settings. A large category points at a few large things worth a decision. A thousand small files rarely are.

How to keep it from piling up

• Turn on Empty Trash automatically in Storage settings, so the Trash doesn't keep what you've already decided to remove.
• Uninstall apps with their uninstaller when they have one, and remove their caches when you remove them.
• Clear Downloads as you go, once each installer has done its job.
• Take a short look every month or two. A category that has grown since last time is where to look.

The post What is safe to delete on a Mac? goes folder by folder through everything else, including what never to touch.

How the app does it

Wombit is a native Mac app that shows what's using your storage, explains every item in plain language, and clears it safely: Trash first, undoable and logged. It reads only names, sizes and dates, and file names and paths never leave your Mac.

Explanations come from a catalog written and checked by hand, with sources. Items no rule explains get a Best guess, written on your Mac by Apple Intelligence and labelled as a guess. Each item the catalog knows gets one of four levels:

• Safe: the owner recreates it and nothing is lost, such as app caches, crash reports and apps' downloaded updates. These start checked.
• Usually safe: it comes back at a cost, such as shared caches in /Library or an old macOS installer.
• Review first: it may be the only copy, such as downloads, iPhone backups and an app's data folder. Nothing starts checked.
• Managed by macOS: temporary files, swap and snapshots are explained and left to macOS's own mechanism, never moved.

Only Safe items count in the headline number. Hard links and APFS clones count once, so shared data isn't added twice, and folders macOS didn't let it read are listed, not skipped.

• ~/Library/Caches/*

  App caches

  Data that apps and macOS services keep so they can load things faster. Apps create it again when they need it.

  Safe · Moves it to the Trash

• ~/Library/Logs/DiagnosticReports/*

  Crash and diagnostic reports

  Reports macOS saves when an app crashes, stops responding or uses a lot of resources. You can view them in the Console app.

  Safe · Moves it to the Trash

• ~/Library/Caches/*.ShipIt

  Squirrel update files (ShipIt)

  Updates that apps built with Electron, such as VS Code, downloaded and staged here before installing them, plus the updater's logs.

  Safe · Moves it to the Trash

• ~/Downloads/*.{dmg,DMG,iso,ISO,pkg,PKG,mpkg,xip}

  Disk images and installer packages in Downloads

  Disk images and installer packages you downloaded, often for apps you've already installed.

  Review first · Moves it to the Trash

• ~/Library/Application Support/*

  Application Support folders

  Data that apps create and manage for you, such as libraries, databases, downloads and settings, in a folder for each app.

  Review first · Explained only: the app shows you how

The analyzer, the map, the explanations, Undo, Put Back and Empty Trash are free. Cleanup, the Apple Data actions for iPhone backups, installers and large old files, and the uninstaller, which shows what each app left behind and why each file belongs to it, are PRO: one payment of $4.99 with lifetime access.

Every Pro tool's review is free to open, so you see what would go and why before you buy.