com.apple.bird taking up space on a Mac is almost never about bird's own folders. bird is the macOS process that syncs iCloud Drive, and the space people find under its name is nearly always iCloud Drive's downloaded files, or a sync that hasn't finished yet.
The supported fixes are iCloud Drive's own. Use Remove Download in Finder for files you don't need on this Mac, turn on Optimize Mac Storage so macOS removes older downloads when space is needed, and let a stuck sync finish. All three keep your files in iCloud and on your other devices.
Don't delete bird's folders by hand. Apple doesn't document what bird keeps in them, removing them doesn't remove the files that use the space, and the folder next to them, Mobile Documents, holds your documents: deleting there deletes them from iCloud and every device.
What the bird process is
Most of what macOS does happens in background processes with short, odd names. bird is one of them, and it only draws attention when it's busy for a long time or when a folder with its name turns up in a disk map.
What is bird on a Mac?
Apple's manual page for bird, which comes with macOS, describes it as one of the system daemons behind Documents in the Cloud, the document syncing that iCloud Drive is built on. A daemon is a process that runs in the background, with no window or menu of its own.
The same page says bird has no configuration options and that users shouldn't run it by hand. There's nothing to set up: you manage iCloud Drive in System Settings and Finder, and bird does the syncing behind them.
Is bird a virus?
No. It's part of macOS, it's described in a manual page Apple ships with the system, and it works for iCloud Drive. Seeing it in Activity Monitor is normal.
If you want to know more about a process, Activity Monitor can show it. Select the process, then double-click it or click the Info button to see details about it.
What is cloudd?
cloudd is bird's neighbour. Its manual page calls it the system daemon behind CloudKit, and Apple's developer documentation describes CloudKit as the way apps move data between themselves and iCloud, so the same data reaches all of your devices.
So bird keeps documents in iCloud Drive in step, and cloudd carries the iCloud data apps keep through CloudKit. Apple adds that CloudKit provides minimal offline caching and relies on the network being there.
Which other processes take part?
A few more names turn up around iCloud syncing. Each has a manual page of its own, and none of them has settings for you to change.
| Process | What Apple's manual page says | Where you notice it |
|---|---|---|
| bird | A daemon behind Documents in the Cloud | iCloud Drive syncing |
| cloudd | The daemon behind CloudKit | Apps syncing their data with iCloud |
| fileproviderd | Controls how File Provider extensions work with file coordination | Cloud storage apps' folders |
| filecoordinationd | Coordinates access to files by several processes | Rarely noticed |
| nsurlsessiond | Carries out background transfers for apps | Downloads that continue while an app is closed |
Dropbox, OneDrive and Google Drive build on File Provider; the post on Dropbox, OneDrive and Google Drive on a Mac covers how they keep files.
Why is bird using so much CPU?
Because it has syncing to do. A large batch of new files, a first sync after signing in, or thousands of changes at once all mean work for bird. To watch it, open Activity Monitor, type bird in the search field, and look at the CPU and Disk tabs.
Busy for a while after a big change is what you'd expect. Quitting bird isn't a fix Apple documents, and its manual page says users shouldn't run it by hand. If it stays busy for days with nothing changing, check the sync status below. Restarting the Mac is harmless and restarts every background process, bird included.
The folders bird and iCloud Drive use
There are two kinds of folder here, and the difference matters. One holds your iCloud Drive documents. The others hold bird's own data about them.
Where are bird's folders?
On the macOS 27 Mac we checked in October 2026, bird's folders were ~/ and ~/. Depending on the macOS version, there may also be a com.apple.bird folder in ~/; that Mac had none.
Apple doesn't document what's inside them. The name CloudDocs is the one Apple's manual pages use for this service: the manual page for bird's command-line tool calls bird the CloudDocs daemon and refers to its CloudDocs database.
What's the Mobile Documents folder?
~/ is iCloud Drive's own folder: your documents, with a folder for each app that stores files in iCloud. The catalog's iCloud Drive entry explains it: downloaded files take space, files with a cloud icon are only in iCloud, and deleting a file there deletes it from iCloud and your other devices.
Its folders look like Apple's other com.apple folders, with names such as com~apple~CloudDocs, but they hold your files. The post on the com.apple folders in your Library shows how they differ from Apple's caches. Manage iCloud Drive only from iCloud Drive in Finder's sidebar.
| Folder | What it is | Catalog level | What to do |
|---|---|---|---|
~/Library/Mobile Documents | iCloud Drive's files | Usually safe | Remove Download in Finder |
~/Library/Application Support/CloudDocs | bird's data | Review first | Leave it to macOS |
~/Library/Group Containers/com.apple.bird | More of bird's data | Review first | Leave it to macOS |
~/Library/Caches/com.apple.bird | bird's cache, on some versions | Safe | Check syncing first |
~/Library/Caches/CloudKit | CloudKit's cache | Safe | Check syncing first |
The two data folders have no entry of their own; the catalog's general rules for Application Support and group containers cover them, which is why they're Review first. The two caches fall under its general cache rule.
Why can't you open these folders?
They're out of sight twice over. Your Library folder is hidden in Finder by default, and Finder's hidden files have their own post. On top of that, macOS keeps these folders private: on the Mac we checked, a tool without Full Disk Access couldn't even read their sizes.
That protection is a hint in itself. macOS guards these folders from other apps, which is a good reason to leave them to the service that owns them.
How do you tell bird's space from iCloud Drive's?
Look at System Settings › General › Storage. Apple says the iCloud Drive category contains all files stored in iCloud Drive, and that System Data holds what fits no other category, including caches. So downloaded documents count under iCloud Drive, and bird's cache would count in System Data with every other cache.
If iCloud Drive is the large figure, the space is your documents, and Remove Download is the fix. If System Data is the large one, look at everything it holds; see what System Data holds.
What else is easy to mistake for iCloud's cache?
Two hidden stores at the top of the disk: the Spotlight index, and the database of earlier versions that apps such as TextEdit keep as you edit. Both belong to macOS, not to iCloud Drive. See the Spotlight index's size and document versions on a Mac.
Why com.apple.bird is taking up space
When bird's activity or iCloud Drive's footprint grows, there's usually a plain cause. These are the common ones, and each has its own fix.
A big first sync
Turning on iCloud Drive, turning on Desktop & Documents Folders, or signing in on another Mac all give bird a lot to move at once. Apple says turning on Desktop & Documents moves both folders into iCloud Drive, and that signing in again brings your iCloud documents back onto the Mac.
Until that settles, bird is busy and the space moves around. Give it time, with the Mac awake, plugged in and online, before deciding something is wrong.
Optimize Mac Storage is off
Without it, macOS keeps a downloaded copy of everything. Apple puts it plainly: if space isn't needed, the full contents of iCloud Drive remain on your Mac. Even with it on, nothing is removed until the Mac needs room, so a Mac with lots of free space can hold every file either way.
A sync that's stuck
Files that can't reach iCloud stay on the Mac, at full size, whatever your settings say. Apple's status icons name the reasons: Waiting to Upload means a file isn't in iCloud yet, Out of Space means your iCloud storage is full, and Ineligible usually means an item is over the 50 GB limit.
None of those can be removed from the Mac to save space, because iCloud doesn't have them. That's why a stuck sync looks like bird hoarding space: the files have nowhere to go.
Lots of small files
Every file in iCloud Drive is something bird keeps in step. Apple doesn't publish a limit on how many files iCloud Drive handles well, but folders with tens of thousands of small files, such as code projects with their node_modules folders, mean far more items to track than a few large videos.
If you keep developer projects in Documents with Desktop & Documents on, they're in iCloud Drive too. Consider keeping them in a folder outside iCloud Drive, with a separate backup.
Folders kept downloaded
Keep Downloaded tells macOS never to remove an item's download, even when space is needed. It's useful for the folder you work from, and easy to forget on a large one. Look for its icon in the iCloud Status column, described below.
Files that don't belong in iCloud Drive
Some files make poor passengers. Anything over 50 GB can't be stored in iCloud at all, and shows as Ineligible. Very large files close to that limit take a long time to upload, and while they wait, they hold space on the Mac and keep bird busy.
Large disk images, video projects and archives you rarely open are often better kept on an external drive, with their own backup. That's a choice about where files live, not a cleanup, and it takes them out of iCloud Drive on every device.
Check iCloud Drive's sync status in Finder
Before you change anything, find out whether iCloud Drive is still working. Finder shows it, in the sidebar and file by file.
How do you see whether iCloud Drive is still syncing?
Hold the pointer over iCloud Drive in Finder's sidebar, then click the status or information icon that appears. Apple says a pie chart next to iCloud Drive shows the overall progress of files moving to and from iCloud, filling as transfers finish.
How do you see each file's status?
- Open a Finder window and click iCloud Drive in the sidebar.
- Choose View › as List.
- Choose View › Show View Options, then select iCloud Status.
A column now shows each item's status. Apple notes that status icons usually appear next to names without the column too, except for downloaded items, which look like any other file.
| Status | What it means | Can its space be freed? |
|---|---|---|
| In iCloud | Stored only in iCloud | It's already free |
| Downloaded | Up to date here and in iCloud | Yes, with Remove Download |
| Keep Downloaded | Kept on the Mac even when space is needed | Only after you turn that off |
| Waiting to Upload | Not yet stored in iCloud | Not until it uploads |
| Out of Space | Your iCloud storage is full | Not until there's room in iCloud |
| Ineligible | Can't be stored in iCloud, usually over 50 GB | Only by moving it out of iCloud Drive |
| Pie chart | A transfer is in progress | After it finishes |
What does bird do when you open a file that's only in iCloud?
It downloads it. An item marked In iCloud is listed in Finder but stored only in iCloud, so opening it needs an internet connection, and the file takes its full size on your Mac once it's down. It stays until you remove the download or Optimize Mac Storage removes it.
What do you do with files stuck at Waiting to Upload?
Keep the Mac awake and online for a while, signed in to iCloud. If files show Out of Space, free some iCloud storage or choose a larger plan: open System Settings, click your name, click iCloud, and see what's using it.
Ineligible items won't upload however long you wait. Move them out of iCloud Drive to a folder on your Mac or an external drive. Apple says dragging an item out of iCloud Drive copies it to your Mac and removes it from iCloud Drive on all your devices.
What if your iCloud storage is full?
Then nothing new reaches iCloud, and bird can't finish. To see what's using it, open System Settings, click your name, click iCloud, then click Manage. The bar shows your total use by category, and clicking an app or feature shows how much it stores.
iCloud Drive shares that storage with iCloud Photos, iPhone and iPad backups, iCloud Mail and more. Every Apple Account gets 5 GB free, and iCloud+ adds more. Backups of devices you no longer have are often the easiest space to recover: click Backups, select one and click Remove.
Apple warns that removing the backup of an iPhone or iPad you still use stops its automatic iCloud backups. Remove only backups you're sure you don't need, and the Out of Space files on your Mac start uploading once there's room.
How long should a first sync take?
Apple doesn't publish times. It depends on how much there is and on your connection. Watch the pie chart in the sidebar rather than the clock, and leave the Mac running overnight if there's a lot.
To see whether space comes back as the sync finishes, note the free space each day for a few days. The post on tracking disk usage over time covers ways to do that.
The supported ways to make iCloud Drive release space
macOS gives you two tools for iCloud Drive's footprint, one immediate and one automatic. Both keep the files in iCloud, and neither needs you to go near bird's folders.
How do you remove a download?
- Open a Finder window and click iCloud Drive in the sidebar.
- Find files or folders you don't need on this Mac. In list view, sort by Size.
- Control-click them and choose Remove Download.
The items stay in iCloud Drive with a cloud icon, still listed in Finder and on your other devices. Open one and it downloads again. To bring several back before going offline, Control-click them and choose Download Now.
How do you turn on Optimize Mac Storage?
- Open System Settings and click your name at the top of the sidebar.
- Click iCloud, then click Drive, and make sure iCloud Drive is on.
- Turn on Optimize Mac Storage, then click Done.
Apple says your Mac can then store documents in iCloud automatically when more space is needed. It acts when space runs short, not the moment you switch it on. The steps are the same in macOS 26 Tahoe and macOS 27 Golden Gate.
How do you undo Keep Downloaded?
Control-click the item in iCloud Drive and choose Keep Downloaded again, so the checkmark disappears. From then on, Optimize Mac Storage can remove its download when space is needed, and Remove Download works on it at once.
Does Remove Download change your other devices?
No. It removes the copy on this Mac only. The item stays in iCloud Drive, on your iPhone, iPad and other Macs, and on iCloud.com. Each device keeps its own downloads, so freeing space on one Mac leaves the others as they were.
What does Store in iCloud in Storage settings do?
System Settings › General › Storage offers a recommendation called Store in iCloud. Apple describes it as storing your Desktop and Documents files in iCloud Drive, your photos and videos in iCloud Photos and your messages in iCloud, while keeping recently opened files on your Mac when space is needed.
It's a bigger change than Optimize Mac Storage alone. It moves two of your most-used folders into iCloud Drive, which means a first sync for bird and more of your iCloud storage in use. If you only want iCloud Drive to free space, turning on Optimize Mac Storage in iCloud's Drive settings does that part on its own.
Which method fits?
| Method | Frees space | Files stay in iCloud? | How to undo it |
|---|---|---|---|
| Remove Download | At once | Yes | Open the file, or Download Now |
| Optimize Mac Storage | When space is needed | Yes | Turn it off |
| Turning off Keep Downloaded | Lets the two above work | Yes | Turn it on again |
| Signing out without keeping copies | At once | Yes | Sign in again |
| Deleting the file | Once the Trash empties | No, deleted everywhere | From the Trash, for 30 days |
Apple says items moved to the Trash from iCloud Drive are emptied from it automatically after 30 days, whatever Finder's settings say. Until then, File › Put Back returns them.
A worked example
Say Storage settings shows iCloud Drive at 70 GB on a Mac with 15 GB free, and bird has been busy for two days. In Finder, the iCloud Status column shows most items as Downloaded, and a 12 GB folder of videos as Out of Space.
The videos can't leave the Mac until iCloud has room, so start there. In Manage, remove the backup of an old iPhone, and the upload begins. Then Control-click two finished project folders and choose Remove Download, and turn on Optimize Mac Storage. bird's own folders were never part of it.
Why not just delete what's large?
Because deleting in iCloud Drive deletes from iCloud and every device that uses it. If you no longer need a file anywhere, that's fine. If you only need room on this Mac, Remove Download gives the same space and keeps the file. The post on iCloud Drive taking up space goes through every case.
Signing out of iCloud as a last resort
Signing out of iCloud, or turning off iCloud Drive, is sometimes suggested as a reset when bird won't settle. It's a big step, and Apple describes exactly what it does to your files.
What happens to iCloud Drive files when you sign out?
Apple says you're asked whether to keep copies of your documents and of data from Contacts, Calendar, Reminders and Messages. If you choose not to, your documents and data stored in iCloud are removed from your Mac. If you keep them, they stay but stop updating with your other devices.
When you turn off iCloud Drive or sign out, Apple says new Desktop and Documents folders are made in your home folder. If you keep a local copy of your files, they're copied to a folder called iCloud Drive (Archive) in your home folder, at their full size.
Does signing out fix a stuck sync?
Apple doesn't document it as a fix. People on Apple's forums report it helping, which makes sense of a kind: when you sign in again, Apple says your iCloud documents and data reappear on your Mac, so everything syncs afresh. That's a full sync again, with bird busy for a while.
Your files stay in iCloud throughout, on your other devices and on iCloud.com. What's at risk is anything on this Mac that iCloud doesn't have yet.
What should you do before signing out?
- Check for Waiting to Upload items in the iCloud Status column. Until they reach iCloud, the copy on this Mac is the only one.
- Copy anything stuck in that state to a folder outside iCloud Drive.
- Back up the Mac with Time Machine, which can only include files that are downloaded.
- Decide whether to keep a copy. Keeping one fills your disk; not keeping one means downloading again later.
What about turning off Desktop & Documents?
It's a smaller step, and it frees no space by itself. Apple says that when you turn off Desktop & Documents Folders, the files saved there stay in iCloud Drive, and new files are saved to Desktop and Documents folders on your Mac from then on.
So the old files are still in iCloud Drive, in folders named Desktop and Documents, and still downloaded unless you remove them. Turn it off only if you want those folders on this Mac alone, not to make room.
What else does signing out change?
Everything that uses your Apple Account in iCloud on this Mac. Apple says you're also asked about iCloud Photos downloads, that Safari's iCloud Tabs list is no longer available, and that your data stays available on your other devices. Sign out only when the gentler fixes have failed.
| Option | Frees space on this Mac? | What's at risk |
|---|---|---|
| Remove Download | Yes, at once | Nothing; the file stays in iCloud |
| Optimize Mac Storage | Yes, when needed | Nothing |
| Turning off iCloud Drive, keeping a copy | No: the archive is full size | Files stop syncing |
| Signing out, keeping copies | No | Copies stop syncing |
| Signing out, not keeping copies | Yes | Anything not yet uploaded |
Why deleting bird's folders by hand is a bad idea
Search for this problem and you'll find advice to delete bird's folders and restart. Here's why that's the wrong place to start.
Is it safe to delete com.apple.bird?
The cache folder in ~/, where a Mac has one, falls under the catalog's general cache rule, so it's Safe in the catalog's sense: bird recreates it. But it rarely holds the space you're looking for, and clearing it doesn't fix a sync that's stuck.
The folder in Group Containers and the CloudDocs folder are Review first. Apple doesn't document what bird keeps there, macOS protects them, and nothing about them is a cache you've been told is disposable. Leave them to macOS. The post on what deleting Library caches does covers ordinary caches.
Why do some guides say to delete the CloudDocs folder?
Forum threads suggest it as a way to reset iCloud Drive. Apple doesn't document doing so, and it isn't where your documents' space is. Those live in Mobile Documents, a few folders away in the same Library, where one wrong click deletes files from iCloud and every device.
If something is truly broken, Apple Support can look at it with you. That's a better route than removing data an Apple service depends on, with no way to check what it held.
What about Terminal fixes?
Apple includes a command-line tool for bird, described in its manual page as managing the CloudDocs daemon. It's command-line only, with no app or menu, and nothing in this post needs it. Don't paste commands from a forum into Terminal to reset iCloud: they can remove data with no undo.
Everything that frees iCloud Drive's space goes through Finder and System Settings: Remove Download, Optimize Mac Storage, Keep Downloaded, and, at the end of the list, signing out.
What if you've already deleted bird's folders?
If they're still in the Trash, select them and choose File › Put Back, then restart the Mac. Finder's Move to Trash can be undone until the Trash is emptied, which is the reason to empty it only once you're sure.
If the Trash is already empty, check iCloud.com first: what you see there is what iCloud has. Restart, give iCloud Drive time, and watch the status in Finder's sidebar. If files never settle, Apple Support is the place to go next, not another folder.
When is it time to contact Apple Support?
When the gentle steps have run out. If items stay at Waiting to Upload for days with room in iCloud, the Mac awake and online, and a restart done, or if iCloud Drive in Finder shows errors you can't explain, Apple Support can look into it with you.
Will clearing bird's cache make your Mac faster?
No. Clearing a cache frees space; it doesn't make a Mac faster, and bird rebuilds what it needs. If bird is using a lot of CPU, it's syncing. Let it finish, and check the status icons if it never does.
How the app does it
Wombit shows what's using your storage and explains every item in plain language. iCloud Drive's folder appears on the map with the space its downloaded files take, explained from the catalog: what it holds, why deleting there deletes everywhere, and how Remove Download and Optimize Mac Storage free the space instead.
iCloud Drive is Usually safe, and the app never removes it: cloud sync folders and everything in them are on the list of places it doesn't touch. bird's cache in Caches is Safe under the general cache rule, and its CloudDocs and group container folders are Review first, so they never start checked.
~/
Library/ Mobile Documents The iCloud Drive files that are downloaded to this Mac, including the iCloud folders that apps use.
Usually safe · Explained only: the app shows you how
~/
Library/ 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/ Application Support/ * 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
~/
Library/ Group Containers/ * Shared folders where apps from the same developer, and their extensions and widgets, keep data they all use.
Review first · Explained only: the app shows you how
macOS keeps iCloud Drive and other protected folders private until you allow an app to read them. With Full Disk Access, the scan measures them; without it, the app lists them as folders it skipped rather than guessing. File names and paths never leave your Mac.
The scan, the map, the explanations and System Data explained are free. Cleanup is PRO: one payment of $4.99 with lifetime access. Every Pro tool's review is free to open, so you can see what would go and why before you buy.
Frequently asked questions
What is the bird process on my Mac?
bird is part of macOS. Apple's manual page describes it as one of the background services behind Documents in the Cloud, the syncing iCloud Drive is built on. It has no settings, and Apple says users shouldn't run it by hand.
Why is com.apple.bird taking up so much space?
Usually it isn't bird's own folders but iCloud Drive's downloaded files, or files that can't upload yet. Check the iCloud Status column in Finder. Use Remove Download for files you don't need on this Mac, and turn on Optimize Mac Storage.
Is it safe to delete com.apple.bird?
A com.apple.bird folder in Caches is an ordinary cache that bird recreates, but clearing it rarely frees much or fixes a stuck sync. Leave bird's CloudDocs and group container folders alone: Apple doesn't document them, and macOS protects them. Never delete files in Mobile Documents, which is iCloud Drive itself.
Why is bird using so much CPU?
Because it's syncing: a first sync, a large batch of new files or many changes at once. It settles when the work is done. If it stays busy for days, check for files stuck at Waiting to Upload or Out of Space in Finder.
What is cloudd on a Mac?
cloudd is the macOS process behind CloudKit, which apps use to keep their data in iCloud and on all your devices. Like bird, it has no settings. It works alongside bird, which handles iCloud Drive's documents.
What happens to my iCloud Drive files if I sign out of iCloud?
Apple says you're asked whether to keep copies. If you don't, your iCloud documents are removed from the Mac but stay in iCloud and on your other devices. If you do, the copies stay but stop syncing. Signing in again brings them back.
How do I make iCloud Drive use less space on my Mac?
In Finder, Control-click iCloud Drive items you don't need on this Mac and choose Remove Download. Then turn on Optimize Mac Storage in System Settings, under your name, iCloud, Drive. Both keep the files in iCloud.
Sources
- Store files in iCloud Drive on Mac · Apple
- Work with folders and files in iCloud Drive · Apple
- Check your iCloud Drive file and folder status on Mac · Apple
- If you sign out of your Apple Account settings on Mac · Apple
- Turn off Desktop & Documents Folders on your Mac · Apple
- View information about Mac processes in Activity Monitor · Apple