Mobile Documents Folder Huge on Your Mac? Don't Delete It Directly
~/Library/Mobile DocumentsDon't delete ~/Library/Mobile Documents. That folder is your actual iCloud Drive: every file in it also lives in Apple's cloud and on your other devices, and deleting files from it locally tells iCloud to delete them everywhere. The size is usually legitimate, and evicting local copies shrinks the folder without touching a single file in iCloud.
What it is
Mobile Documents is the on-disk home of iCloud Drive. macOS keeps it inside your user Library at ~/Library/Mobile Documents, and Finder disguises it: click into it and the window title changes to iCloud Drive. List it in Terminal instead and you'll see one container per app that syncs through iCloud, with raw names Finder never shows. The one called com~apple~CloudDocs is the general iCloud Drive area from the Finder sidebar, and the others (com~apple~Pages, iCloud~com~apple~iBooks, containers for third-party apps) hold each app's synced documents.
It grows for one honest reason: you and your apps keep putting files in iCloud. Turning on Desktop and Documents syncing is the usual culprit, since that routes both of those folders through this directory. The local number can also mislead you. macOS streams iCloud files on demand, so some files are fully downloaded and take real disk space, while others are cloud-only placeholders that take almost none. A huge Mobile Documents folder often just means macOS kept a lot of local copies because your disk had room at the time.
Is it safe to delete?
No. Do not drag Mobile Documents to the Trash, and do not rm it in Terminal. iCloud treats a local delete as an instruction, so removing files here removes them from iCloud and from every iPhone, iPad, and Mac signed into the same Apple Account. Best case, macOS notices, re-syncs the whole folder, and you gain nothing. Worst case, files you wanted are gone, and you have 30 days to recover them from Recently Deleted on iCloud.com before they disappear for good.
The safe move is eviction, not deletion. Right-click any file or folder inside iCloud Drive in Finder and choose Remove Download. The file stays in iCloud and stays visible in Finder with a cloud icon, but its local bytes are freed. System Settings can do this automatically too: turn on Optimize Mac Storage and macOS evicts older files on its own as the disk fills. Diskmack deliberately does not scan inside this folder, because walking it could force macOS to download everything; it flags the folder and points you to your iCloud settings instead.
How to check its size
In Finder: In Finder, choose Go > Go to Folder, enter ~/Library and press Return. Select the Mobile Documents folder and press Command-I. Get Info shows the local on-disk size, which is what matters for a full Mac.
In Terminal:
du -sh ~/Library/"Mobile Documents"Keep the ~ outside the quotes so the shell expands it to your home folder. Note that du counts only downloaded files; evicted, cloud-only files add almost nothing.
How to clean it
- Free space without deleting anything first: open iCloud Drive in Finder, right-click a large folder you rarely open, and choose Remove Download. The files stay in iCloud and re-download when you next open them.
- Turn on automatic eviction: System Settings > your name > iCloud > Optimize Mac Storage. macOS keeps recent files local and quietly evicts older ones when the disk gets tight.
- If Desktop and Documents syncing is inflating the folder and you never wanted it, go to System Settings > your name > iCloud > iCloud Drive and turn off Desktop & Documents Folders. Read the dialog carefully: your files stay in iCloud, and you will need to move them back into the local folders yourself.
- To genuinely delete files, do it inside the iCloud Drive view in Finder, file by file, knowing each delete propagates to all your devices. Deleted files sit in Recently Deleted on iCloud.com for 30 days.
- Never delete the Mobile Documents folder itself, and never remove the com~apple~CloudDocs container inside it. Both hold your real documents, not caches.
Anything you delete inside iCloud Drive disappears from every device on your Apple Account. It stays recoverable for 30 days under Recently Deleted at iCloud.com, then it is gone.
Will it come back?
Yes, by design, and that is fine. Mobile Documents mirrors whatever is in your iCloud Drive, so as long as syncing is on, the folder exists and holds something. Evicted files re-download when you open them, and macOS re-caches local copies when you have disk space to spare, so the local size can creep back up after a round of Remove Download. If you deleted the folder outright, macOS would rebuild it and re-download everything, which is exactly why deleting it gains you nothing.
Common questions
Why does Mobile Documents show a different size than my iCloud usage?
du and Get Info count local bytes only. Files evicted to the cloud take almost no space on your Mac but still count against your iCloud plan, so the two numbers rarely match. A Mac with lots of free disk space tends to hold more local copies, which pushes the folder's size closer to your total iCloud usage.
Can I move Mobile Documents to an external drive?
No. macOS manages its location, and syncing breaks if you relocate or symlink it. If local copies are the problem, use Optimize Mac Storage or Remove Download instead. Those keep everything in iCloud while freeing the disk.
Will deleting files here free up my iCloud storage too?
Yes, though not always right away: deleted files sit in Recently Deleted for up to 30 days, and your iCloud quota may not shrink until they clear. The bigger issue is that the deletes sync upward, so the files also vanish from your iPhone, iPad, and any other Mac on the account. If you only want Mac disk space back, evict with Remove Download rather than deleting.
What are the com~apple~CloudDocs and iCloud~ folders inside it?
Each app that syncs through iCloud Drive gets its own container. com~apple~CloudDocs is the general iCloud Drive area you browse in Finder. The others hold documents for specific apps, Apple's and third parties' alike. Deleting a container deletes that app's cloud documents everywhere.