icloud optimize mac storage: on or off, and why it isn't freeing space
by sumit paul · last updated
icloud's optimize mac storage keeps the full contents of icloud drive on your mac while there's room, and removes the local copies of older files only when macos decides space is needed, leaving placeholders you can open later. turn it on if your icloud drive is bigger than your free disk space; leave it off if you work offline or want every file on the mac. it doesn't free space the moment you switch it on, which is why it often looks like it isn't working.
where the setting is
apple menu › system settings › your name › icloud › drive. make sure icloud drive is on, then turn on optimize mac storage. on the same screen, desktop & documents folders moves those two folders into icloud drive, so the setting applies to them too.
three settings have similar names, and people mix them up:
| setting | where | what it does |
|---|---|---|
| optimize mac storage (icloud drive) | system settings › your name › icloud › drive | removes local copies of older icloud drive files when space is needed |
| optimize mac storage (photos) | photos › settings › icloud | keeps smaller versions of photos on the mac; originals stay in icloud |
| optimize storage | system settings › general › storage | removes apple tv movies and shows you've watched; keeps only recent mail attachments |
this article is about the first one.
how it works
- off: every file in icloud drive is kept in full on your mac. icloud is a sync, not extra space.
- on, with plenty of space: apple says that if space isn't needed, the full contents of icloud drive stay on your mac. so on a roomy disk, on and off behave the same.
- on, when space runs low: macos removes the local copies of older files and keeps recently opened ones. removed files show a cloud icon in finder and take almost no space.
- opening a removed file: the whole file downloads first, then opens. it stays on your mac until space is needed again.
apple doesn't publish the exact threshold for "space is needed" or how it ranks files. what you can rely on: recently opened files are kept, older ones go first, and anything marked keep downloaded is never removed.
why it isn't freeing space
it waits until space is needed
this is the usual reason. turning it on doesn't trigger a clean-up. macos removes local copies when the disk gets tight, not when you'd like extra headroom. if you want space now, do it by hand: select files or folders in icloud drive, control-click, and choose remove download. the files stay in icloud.
the files haven't finished uploading
a file can only leave your mac once it's safely in icloud. if your icloud storage is full or uploads are stuck, nothing can be removed. hold the pointer over icloud drive in the finder sidebar and click the status icon to see if it's still syncing, and check your icloud storage in system settings › your name › icloud. if it's full, see icloud storage full.
the files aren't in icloud drive
optimize only touches icloud drive. your downloads folder, your photos library, and desktop and documents (unless desktop & documents folders is on) aren't affected.
you marked them keep downloaded
files and folders marked keep downloaded show an icon next to the name and are never removed. control-click and choose keep downloaded again to clear the checkmark.
you keep opening them
every open downloads the whole file and marks it as recent. big files you use weekly will keep coming back.
on or off?
| your situation | recommendation |
|---|---|
| icloud drive is bigger than your free space | on |
| plenty of free space | either; it behaves like off until space is needed |
| you often work offline (flights, travel) | off, or on with keep downloaded for the folders you need |
| you rely on time machine for icloud drive files | off. time machine backs up what's on the disk, and removed files aren't |
| you store large videos in icloud drive | on helps, but each open downloads the whole video |
before turning it off, check that your mac has room for your entire icloud drive, because the files that were only in the cloud download again.
a note on big files
optimize mac storage works well for documents. for large video it's awkward: a 20 GB clip that was removed needs 20 GB free and a full download before it opens, and then it sits on your disk again. if your large files live in google drive or dropbox instead, feather drive mounts them in finder and streams only the parts an app reads, so they never take their full size on the mac. it doesn't work with icloud, needs macos 26 or later and an internet connection to open files, only sees the files you put in it, and is a paid app with a 3-day free trial.
related
- does icloud drive take up space on your mac?
- icloud storage full: what's filling it and how to free it
- mac storage full: what to do
- how to open any file from the cloud on a mac without downloading it
common questions
should i turn optimize mac storage on or off?
turn it on if your mac's disk is smaller than your icloud drive and you have a reliable connection. leave it off if you have plenty of space, work offline often, or want time machine to back up every icloud drive file.
why didn't turning on optimize mac storage free any space?
it only removes local copies when macos decides space is needed, and it keeps recently opened files. it doesn't clear space the moment you switch it on. to free space now, control-click files in icloud drive and choose remove download.
does optimize mac storage delete my files?
no. it removes only the local copy and leaves the file in icloud, with a placeholder on your mac. the file downloads again when you open it.
what happens if i turn optimize mac storage off?
with it off, macos keeps the full contents of icloud drive on your mac, so files that were only in the cloud download again. make sure you have room for your whole icloud drive first.
how do i keep a file on my mac with optimize on?
control-click it in finder and choose keep downloaded. macos then won't remove it from your mac when space runs low.