The Mac storage categories are the groups System Settings › General › Storage sorts your used space into: Applications, Documents, Photos, iCloud Drive, iOS Files, Messages, System Data and a dozen more.
On macOS 27 Golden Gate, as on macOS 26 Tahoe, each one counts a particular kind of file, and Apple's description of each is the same in both versions.
You only see the categories you have something in. A Mac without Xcode has no Developer category, and one that has never backed up an iPhone has no iOS Files. Apple's guide says it plainly: the categories you see vary with the apps and files on your Mac.
Most categories have an information button. Click it to open a list of what that category holds, where you can delete items or show them in Finder; a few lists add their own tools. Other Users & Shared, macOS and System Data show only a size, though the macOS button does report what Apple Intelligence uses.
This post goes through every category: what it counts, what its information button lets you do, and where to manage it when the button isn't enough. To learn how to open Storage settings and read the bar at the top, see how to check storage on a Mac.
The Mac storage categories at a glance
Apple's guide describes most categories in a sentence each, and lists a few as size-only. The tables below group them by what they hold, with what the information button gives you. Sections further down go through each one.
Your apps and files
| Category | What it counts | What you can do from Storage settings |
|---|---|---|
| Applications | Apps you installed, not the ones that come with macOS | See apps by size and last use, then delete them |
| Documents | Files in your home folder that fit no other category | See large files and downloads, browse folders, delete |
| iCloud Drive | iCloud Drive files kept on this Mac | Manage downloads in Finder instead |
| Trash | Items waiting to be erased | Erase single items, or empty the Trash |
| iOS Files | iPhone and iPad backups and software files | Delete backups and software files |
| Developer | Xcode's build data, caches and support files | Delete build data, caches and device support |
Apple's apps and their libraries
| Category | What it counts | What you can do from Storage settings |
|---|---|---|
| Photos | Your System Photo Library | Manage it in Photos instead |
| Music | Your Music library's files | Remove music videos |
| TV | Apple TV purchases and downloads | Remove movies and shows you can download again |
| Books | Books you've downloaded | Remove books you can download again |
| Podcasts | Downloaded episodes | Remove episodes you can download again |
| Your mail and its attachments | Manage it in Mail instead | |
| Messages | Conversations and their attachments | See the larger attachments and delete them |
| Music Creation | GarageBand, Logic Pro and MainStage content | Remove sound library content |
Size only
| Category | What it counts | What you can do from Storage settings |
|---|---|---|
| Other Users & Shared | Files of other accounts, and shared files | No button; see the section below |
| macOS | macOS's own apps and files | Shows the space Apple Intelligence uses |
| System Data | Everything no other category claims | No button |
The descriptions come from Apple's guide to Storage settings, which reads the same for macOS 27 and macOS 26. What each button offers comes from Apple's guides, from what independent testers have documented, and from the labels macOS 27 itself uses in these windows.
How Storage settings sorts your files
The categories are an estimate, worked out in the background each time you open Storage settings. Knowing how they're put together explains most of the puzzles people run into.
Do the categories match folders on your Mac?
No. Apple's older storage guides said it directly: the categories don't correspond to specific folders. Storage settings sorts files by what they belong to, such as an app's library or your home folder, and the result doesn't line up with any one folder you can open in Finder.
Your Music library, for instance, counts under Music, but other audio files in your Music folder may not. Howard Oakley of Eclectic Light found that Storage settings recognized under 50 GB of a Music folder that held over 100 GB. Whatever no category claims ends up in System Data.
Why do some categories appear and others don't?
A category appears when there's something in it. Developer needs Xcode, iOS Files needs a device backup or a software file, and Music Creation needs GarageBand, Logic Pro or MainStage content. A category with nothing in it simply isn't listed.
Each account also sees its own view. On a Mac with several accounts, your files are sorted into categories for you, and everyone else's files appear in your Other Users & Shared.
What can you do in an information window?
Most windows list items with their size, and some add the kind and when you last opened each one. Select an item and click Delete, or click Show in Finder to look at it first. Apple's guide adds that some categories let you open an app to delete files there.
Before you click Delete, know what it does. macOS asks you to confirm, then deletes the item immediately; it doesn't go to the Trash, and you can't undo it. When in doubt, use Show in Finder and move the item to the Trash there instead.
Why does the bar keep changing?
Storage settings counts in the background, so categories can read Calculating… or shift for a minute after you open it. Snapshots, swap and caches also grow and shrink by themselves. Give it a moment before you compare numbers.
Applications
Applications counts the apps you've installed. Apple's guide leaves out the apps that come with macOS, which count under macOS, and notes that on a partitioned disk only apps on the startup partition count.
What does the Applications list show?
It lists your apps with each one's size and when you last opened it, and you can sort by either. An app you've never opened says so. The list can also show what each app is built for: macOS's labels include Apple Silicon, Intel and Universal, plus iOS for iPhone and iPad apps and Web for web apps.
Eclectic Light notes that the list helps you find apps that run only on Intel processors, and duplicates of the same app. Both are worth a look: an old Intel-only app may need Rosetta, and a second copy of an app takes its full size again.
What does Applications leave out?
Only the app itself. An app's caches, settings and data live in your Library folder and count elsewhere, mostly in System Data. A large app can leave behind more than it weighed.
Full macOS installers, such as Install macOS Tahoe, sit in the Applications folder and count here too. Once you've upgraded, each one is many gigabytes you can download again if you need it.
Can you get a deleted app back?
It depends on where it came from. Apps from the App Store can be downloaded again from your purchases in the App Store, and macOS describes this list as a place to remove apps you can download that way.
Apps from other sources need their installer or the developer's website. Paid apps may also ask for their license key again, so make sure you have it before you remove them.
Should you delete apps from this list?
For apps with nothing to clean up, it's quick. For apps that came with their own uninstaller, or that install helpers and background items, use the uninstaller, or remove the app in Finder after checking what it leaves behind in your Library folder.
Remember that Delete here is immediate. If you think you might want an app back and can't download it again, move it to the Trash in Finder instead.
Documents and iCloud Drive
These two categories hold most of your own files. Documents is the broader of the two, and the one with the most useful tools.
What counts as Documents?
Apple's guide says Documents holds files in your home folder that aren't in other categories, such as Pages documents and PDFs. It also includes photos and videos that your photo library doesn't manage, like an image someone sent you with AirDrop.
So downloads, disk images, archives, exported videos and screen recordings all count here. Files elsewhere in your home folder count too, not just those in the Documents folder.
What can you do in the Documents window?
More than in any other category:
- Buttons switch between your large files and your downloads.
- Columns for Name, Kind, Last Accessed and Size sort the list.
- File Browser shows your folders with the space each one uses. Apple notes that folders already counted in another category are dimmed.
Sorting large files by Last Accessed is the quickest way to find a video or disk image you haven't opened in a year. The same immediate-delete rule applies, so use Show in Finder for anything you might want back.
What counts as iCloud Drive?
Apple's guide says it contains the files stored in iCloud Drive, and may include your Desktop and Documents folders if they sync to iCloud Drive. Storage settings counts the copies kept on this Mac, not what's in iCloud.
The tools that matter are in Finder and iCloud settings. Control-click an item in iCloud Drive and choose Remove Download to keep it in iCloud only. Or choose System Settings, click your name, then iCloud and Drive, and turn on Optimize Mac Storage, so macOS does this for older files when space is needed.
What does Store in iCloud do to these categories?
The Store in iCloud recommendation above the categories moves your Desktop and Documents folders into iCloud Drive, your photos into iCloud Photos and your messages into iCloud, and keeps only recent files on the Mac when space is needed. Files then move from Documents to iCloud Drive, and shrink as macOS removes older local copies.
It uses your iCloud storage. If your iCloud plan is nearly full, it can't help.
Photos, Music, TV, Books and Podcasts
The media categories count the libraries of Apple's own apps. Each app has its own way to free space, and those ways are safer than deleting files in Finder.
What counts under Photos?
Apple's guide says Photos holds your System Photo Library, the one Photos uses for iCloud Photos. A second library, such as an old one from another Mac, isn't counted here.
Manage the library in Photos. If you use iCloud Photos, choose Photos › Settings, click iCloud and select Optimize Mac Storage, so full-size originals stay in iCloud. Never remove files from inside the library package in Finder.
What does the Music button offer?
Less than you'd expect. Eclectic Light found that the Music window deals only with music videos you can remove, and macOS 27's own description of the window says the same. To remove songs or albums, use the Music app: Remove Download keeps them in your library to stream.
What about TV, Books and Podcasts?
Apple's guide says each holds purchases from its app that you can remove and download again. Their windows list those items, so you can delete movies, shows, books and episodes you've finished with. Apple singles out TV and Podcasts among the windows most worth opening.
The Optimize Storage recommendation removes Apple TV movies and shows you've already watched, automatically, when space is needed. Podcasts can remove played episodes for you in its own settings.
Why is TV or Music larger, or smaller, than expected?
The categories count what the app's library knows about. Files you added outside the library, or a library on an external drive, may be counted differently or not at all. Eclectic Light noticed TV reporting 36 GB on a Mac whose media lived mostly on an external SSD, so treat these figures as estimates.
Mail, Messages and Music Creation
Three more of Apple's apps get categories of their own. Two of them have useful windows; for Mail, the work happens in Mail.
What counts under Mail?
Apple's guide says Mail contains emails and attachments: the copy Mail keeps on your Mac. Apple doesn't describe a list of messages to delete in Storage settings, so manage the space in Mail.
The Optimize Storage recommendation keeps only recent email attachments on the Mac when space is needed. In Mail, you can also delete messages you don't need, or select a message and choose Message › Remove Attachments.
What does the Messages window show?
Messages counts your conversations with their attachments. Its window lists the larger attachments, so you can select the ones you don't need and click Delete. Apple names Messages among the windows most worth opening.
If you use Messages in iCloud, deleting an attachment on your Mac deletes it on your other devices too. To keep fewer old conversations, choose Messages › Settings, click General and change Keep messages.
What counts as Music Creation?
Apple's guide says Music Creation holds content from GarageBand, Logic Pro and MainStage: instruments, loops, samples and lessons you've downloaded. Its window lets you select sound library content you don't need and delete it.
Anything you remove can be downloaded again from the app's Sound Library menu. Songs that use a removed instrument or loop play without it until you do.
Does Logic Pro 12 count its sounds twice?
No. Apple says Logic Pro 12 and MainStage 4 copy the sound library into a single Logic Pro Library file in your Music folder, and that this needs no extra space on the Mac. The copy shares storage with the older files, so removing those older files frees little while the new library exists.
iOS Files, Trash and Developer
These three hold some of the largest single items on many Macs: device backups, deleted files waiting to go, and Xcode's support files.
What counts as iOS Files?
Apple's guide says iOS Files contains iOS backups and firmware. Its window groups them as device backups and the software files Finder downloads to update or restore an iPhone or iPad.
Software files are the easy win: Finder downloads the current version again when it needs one. Backups need more thought, because a backup of a device you still use may be its only copy. The post on iOS Files in Mac storage goes through both.
What can you do in the Trash window?
The Trash window lists what's waiting in the Trash. You can erase single items, or click Empty Trash to erase them all, and it offers to turn on emptying the Trash automatically after 30 days. Either way, what you erase is gone for good.
Apple's guide notes two exceptions to the figure. Items deleted from iCloud Drive aren't counted, and on a partitioned disk only the Trash on the startup volume is.
What does the Developer category hold?
It appears when Xcode is installed, though Apple's storage guide doesn't list it. Eclectic Light describes it as a way to clean up build files and device support. The labels macOS 27 uses in its window show what it can list:
| Entry | What it is | What happens if you delete it |
|---|---|---|
| Project Build Data and Indexes | Xcode's DerivedData for each project | Xcode rebuilds it on the next build |
| Xcode Caches | Data Xcode and its build tool keep to save work | Xcode fetches or makes it again |
| Project Archives | Builds you archived, with their debug symbols | Gone; keep the ones you shipped |
| iOS, watchOS, tvOS, visionOS and macOS Device Support | Symbol files copied from devices you connected | Copied again when you connect that version |
| Simulator Support | Files Xcode uses to run apps in Simulator | Manage simulators and runtimes in Xcode |
| Command Line Tools and Kernel Development Kits | Developer tools installed outside Xcode | Reinstall them if you need them |
For simulator runtimes and platforms, Xcode is the better place: choose Xcode › Settings and click Components to see each one with the space it takes. A lot of developer data never reaches this category, though. Docker, package managers' caches and local AI models usually land in System Data.
Other Users & Shared, macOS and System Data
Apple's guide groups these three as categories that only show how much space they take, and says you can't select and delete files in them. Each has a reason.
Other Users & Shared
This category counts files created and modified, or shared, by other user accounts on your Mac, including the Shared folder that every account can reach. On a Mac with one account, it usually means a home folder left behind by a deleted account, or something an app put in the Shared folder.
You manage it in Users & Groups settings and in Finder, not in Storage settings. The post on Other Users & Shared explains where its space hides and how to get it back.
macOS
macOS counts macOS's own apps and files, such as Mail, Terminal and Calculator. Most of them live on a sealed system volume that only Apple's updates change, so there's nothing here for you to delete.
Its information button does one thing: it shows how much of the figure is Apple Intelligence. Eclectic Light documented it on macOS Sequoia, and MacRumors describes the same button on macOS 27. The post on Apple Intelligence storage explains why that figure can grow after an update.
System Data
System Data is everything else: in Apple's words, files that don't fall into the other categories, such as logs, caches, virtual memory files, temporary files, fonts, app support files and plug-ins. macOS manages it, and its size changes with the state of your Mac.
There's no button and no list, because it's a remainder rather than a folder. The post on what System Data is takes it apart piece by piece.
How the categories changed across macOS versions
The categories have been renamed and moved several times. If you follow an older guide, or help someone with an older Mac, the names below will match what they see. The post on what happened to Other storage covers how it became System Data.
| macOS version | Where the categories are | What changed |
|---|---|---|
| High Sierra 10.13 | About This Mac › Storage | iTunes and iBooks share one category; Other users; System includes local snapshots |
| Catalina 10.15 | About This Mac › Storage | Apple TV, Music, Books and Podcasts get their own categories |
| Big Sur 11 | About This Mac › Storage | Apple's guide lists Other for files no category claims |
| Monterey 12 | About This Mac › Storage › Manage | Other becomes System Data, and System becomes macOS |
| Ventura 13 | System Settings › General › Storage | Storage moves to System Settings, with All Volumes |
| Sonoma 14 and Sequoia 15 | System Settings › General › Storage | Other Users becomes Other Users & Shared |
| Tahoe 26 and Golden Gate 27 | System Settings › General › Storage | Apple's guide unchanged since Sequoia |
One change in meaning came with the move from System to macOS. Apple's older guides listed Time Machine's local snapshots under System; its later guides don't mention them for macOS, and snapshots now end up in System Data.
How does macOS 26 differ from macOS 27?
In Storage settings, hardly at all. Apple's guides for the two versions describe the same recommendations, the same categories and the same All Volumes view, word for word, and the steps to open Storage settings are the same.
What differs is what goes into the categories. On macOS 27, Apple says the next generation of Apple Intelligence becomes available automatically on eligible Macs after the update, so the macOS category can grow by several gigabytes without you asking for anything.
What did older versions offer that's gone?
In Monterey and earlier, Manage in About This Mac opened a separate window with the categories in a sidebar. Apple's Monterey guide lists a fourth recommendation there, Reduce Clutter, for finding large items to delete, which the guide for macOS 27 no longer mentions.
In that window, iCloud Drive, Photos, Music Creation and Mail showed general recommendations rather than lists of files. Today Music Creation has a list of its own, and the other three are still managed mostly in their apps.
Categories on a Mac with several volumes or disks
Most Macs have one internal disk with one container, and Storage settings shows one bar. A few setups change what the categories cover.
What if your Mac has more than one volume?
Apple's guide says that if you see more than one disk in Storage settings, your internal disk has several volumes or containers. Click All Volumes for a bar per volume and container, with the space each one uses and has available.
Volumes in one container share its free space, so a second macOS install or a volume you made for projects takes space from the same pool. The categories describe your startup volume; the other volumes show up as their own bars.
What about a partitioned disk?
Apple adds three notes for a disk split into partitions. Applications counts only apps on the startup partition, Trash counts only the Trash on the startup volume, and the recommendations apply only to the partition that holds your home folder.
So on a partitioned disk, apps and deleted files on the other partition aren't in these figures at all. Check them in Finder or Disk Utility instead.
Do external drives appear in the categories?
No. Storage settings describes your internal disk. Files you keep on an external drive, such as a Photos library you moved, a Logic Pro sound library or a folder of videos, don't count in any category, and freeing space there doesn't change the bar.
For an external drive, select it in the Finder sidebar and choose File › Get Info, or select it in Disk Utility. Items you delete from it wait in that drive's own Trash until you empty it.
Which category to look at first
The largest category isn't always the best place to start. Some are quick wins with nothing lost; others hold your only copy of something.
Which categories are safest to trim?
Start where everything can come back. Software files in iOS Files, Xcode's build data and caches in Developer, and watched movies in TV can all be downloaded or rebuilt. Downloads in Documents that you've already installed or unpacked are often next.
Then move to categories that need a decision: old device backups, Messages attachments, large files you haven't opened in a year. Leave macOS and System Data to the tools that manage them.
- Photos library (Photos)10–500 GB · Managed by macOS
- Device backups (iOS Files)10–200 GB · Review first
- Downloaded episodes (Podcasts)1–250 GB · Usually safe
- Attachments (Messages)5–100 GB · Review first
- Build data (Developer)5–100 GB · Safe
- Sound library (Music Creation)2–70 GB · Usually safe
- One software file (iOS Files)5–15 GB · Safe
Typical ranges on Macs that have these items at all, from the research behind the app's catalog. Many Macs have far less. The level is the one the catalog gives each item.
What should you do with each large category?
| If this category is large | First look at | Where to do it |
|---|---|---|
| Documents | Large files and downloads, sorted by Last Accessed | The Documents window, or Finder |
| Photos | Optimize Mac Storage, or moving the library | Photos |
| iOS Files | Software files, then backups of devices you no longer have | The iOS Files window |
| Messages | The largest attachments | The Messages window, or Messages |
| Developer | Build data and old device support | The Developer window, or Xcode |
| System Data | Snapshots, caches and developer tools | Finder, Disk Utility and the tools themselves |
| Other Users & Shared | Old accounts and the Shared folder | Users & Groups settings and Finder |
Which mistakes are worth avoiding?
- Deleting from a window when you meant the Trash. Delete in Storage settings is immediate and permanent. Use Show in Finder when you're not sure.
- Deleting files inside a library. Photos, Music, TV, Podcasts, Books and Messages keep databases of their files. Remove items in the app, or the library loses track of them.
- Chasing the macOS figure. Nothing in it is yours to delete. If it grew after an update, that's macOS and its models.
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. Where Storage settings gives you categories, it shows the folders themselves on a map, with an explanation for each item from a catalog written and checked by hand, with sources.
System Data, explained splits that one number into named buckets and shows how much it couldn't explain. Apple Data gathers iPhone backups, installers and large old files. These are some of the catalog's entries behind the categories in this post:
~/
Library/ iTunes/ {iPhone,iPad,iPod} Software Updates iPhone and iPad software updates
Software files that were downloaded to update or restore an iPhone, iPad or iPod touch connected to this Mac.
Safe · Moves it to the Trash
~/
Library/ Application Support/ MobileSync/ Backup/ * Backups of an iPhone, iPad or iPod touch that were made on this Mac, one folder for each device.
Review first · Moves it to the Trash
~/
Library/ Developer/ Xcode/ DerivedData Build products, indexes and logs Xcode keeps for every project you've built.
Safe · Moves it to the Trash
~/
Library/ Developer/ Xcode/ Archives/ */ *.xcarchive Copies of each build you archived in Xcode, with the dSYM files needed to read crash reports from that build.
Review first · Moves it to the Trash
~/
Library/ Messages/ Attachments Photos, videos, audio messages and files sent and received in Messages on this Mac.
Review first · Explained only: the app shows you how
/
Library/ Application Support/ GarageBand GarageBand and Logic Pro sound library
Instruments, samples, Apple Loops and lessons that GarageBand, and Logic Pro 11 or earlier, install for everyone on this Mac.
Usually safe · Explained only: the app shows you how
~/
**/ *.photoslibrary A Photos library: your photos and videos, your edits and albums, and the previews Photos makes from them.
Managed by macOS · Explained only: the app shows you how
Each has a level. Safe items, such as software files and DerivedData, start checked in Cleanup and are the only ones counted in the headline number. Usually safe and Review first items, such as backups and attachments, wait for your choice, and Managed by macOS items, such as the Photos library, are explained and left to their app.
Cleanup moves items to the Trash, with Undo and Put Back, rather than deleting them on the spot. Scanning, the map and System Data explained are free. Cleanup and the Apple Data actions for backups, installers and large old files 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.
Frequently asked questions
What are the categories in Mac storage?
Storage settings can show Applications, Documents, iCloud Drive, iOS Files, Photos, Music, TV, Books, Podcasts, Mail, Messages, Music Creation, Trash and, with Xcode, Developer. Three more, Other Users & Shared, macOS and System Data, only show their size. You see only the categories you have something in.
Why are some storage categories missing on my Mac?
A category appears only when there's something in it. Developer needs Xcode, iOS Files needs a device backup or software file, and Music Creation needs GarageBand, Logic Pro or MainStage content. Apple's guide says the categories you see vary with the apps and files on your Mac.
Does deleting in Storage settings move files to the Trash?
No. When you select an item in a category and click Delete, macOS deletes it immediately and says you can't undo it. If you might want something back, click Show in Finder and move it to the Trash there instead.
Why can't I open System Data in Storage settings?
System Data is what's left after every other category is added up, so there's no list of files behind it. Apple says macOS manages its contents and you can't manage them in Storage settings. You deal with its parts in Finder, Disk Utility, Time Machine settings or the apps that made them.
What's the difference between Documents and iCloud Drive in Mac storage?
Documents counts files in your home folder that fit no other category, including downloads and videos outside Photos. iCloud Drive counts the iCloud Drive files kept on this Mac, which can include your Desktop and Documents folders if they sync to iCloud. Removing an iCloud Drive download keeps the file in iCloud.
Why is the Music category smaller than my Music folder?
Storage settings counts what the Music app's library knows about, not everything in the folder. Other audio files, project files and libraries from other apps may count elsewhere, often in System Data. Eclectic Light found under 50 GB counted for a Music folder of over 100 GB.
Is it safe to delete Project Build Data and Indexes on a Mac?
Yes. It's Xcode's DerivedData, the build products and indexes it makes for each project, and Xcode rebuilds it the next time you build. The first build afterwards takes longer. Quit Xcode before you delete it.
Where did Manage storage go on my Mac?
In macOS Ventura and later, storage is in System Settings: choose Apple menu, System Settings, click General, then Storage. In Monterey and earlier it was in About This Mac, under Storage, with a Manage button for the detailed window.
Sources
- Change Storage settings on Mac · Apple
- Find and delete files on your Mac · Apple
- Optimize storage space on your Mac · Apple
- Free up storage space on Mac · Apple
- Find and delete files on your Mac (macOS Monterey) · Apple
- What is System Data in Storage Settings? · Eclectic Light