Desktop & Documents iCloud Sync on Mac: On or Off?

One checkbox moves your two most-used folders into iCloud. Desktop & Documents Folders sync is genuinely useful for multi-Mac people and genuinely surprising for everyone else — because both turning it on and turning it off relocate files in ways nobody expects. Here's exactly what it does, so you can decide with your eyes open.

What turning it on actually does

Enable it in System Settings → your name → iCloud → iCloud Drive → Desktop & Documents Folders (on Sequoia, iCloud Drive lives under the Saved to iCloud section). The effect is a relocation, not a copy:

• Your Desktop and Documents folders stop living at ~/Desktop and ~/Documents and become folders inside iCloud Drive.
• In Finder's sidebar, both folders move from Favorites into the iCloud section.
• Every file in them starts uploading and now counts against your iCloud storage quota. A Desktop full of video projects can swallow a 50 GB plan in an afternoon.
• Your files stay usable throughout — the initial upload just runs in the background, sometimes for hours on a slow connection.

What happens with a second Mac

Turn the same switch on for another Mac and Apple faces a merge problem: two machines can't both own "the" Desktop. Its answer is to keep them separate — the second Mac's existing files land in a subfolder named after that machine, like Desktop – MacBook Air, inside the shared iCloud Desktop folder. From then on, both Macs show the same live Desktop and Documents: save a file on one, and it's on the other's Desktop moments later. If you want one unified set, drag the machine-named folder's contents into the main folder yourself and resolve any name clashes by hand — macOS won't merge them for you.

A pleasant side effect worth naming: once the folders live in iCloud Drive, they're reachable from your iPhone and iPad through the Files app, and from any browser at iCloud.com — your Desktop stops being tied to the machine it's drawn on.

What turning it off does (this is the surprising part)

Flip the checkbox off and your local ~/Desktop and ~/Documents come back — empty. macOS does not move your files home. They stay in iCloud Drive, in folders still named Desktop and Documents, and your Mac keeps access to them there. To actually return everything local:

1. Open iCloud Drive in Finder's sidebar and open its Desktop folder.
2. Select everything (⌘A) and check nothing shows a cloud icon — right-click → Download Now on anything that does.
3. Drag the files into your (now local) Desktop. Repeat for Documents.
4. Once you've confirmed the local copies, delete the leftovers from iCloud Drive if you no longer want them in the cloud.

Doing the download before you disable the sync avoids the worst case: online-only placeholders pointing at files you then delete from iCloud.

So: on or off?

Turn it on if any of these describe you: you work across two Macs and want one Desktop everywhere; you treat the Desktop as your active-project space and want it on your iPhone (Files app) too; or you like that a stolen laptop costs hardware, not files. Turn it off (or leave it off) if your Desktop hosts huge media files, your upstream bandwidth is poor, your iCloud plan is small, or you need documents guaranteed available with no internet — a Mac that can't reach iCloud shows placeholders for anything that was evicted to save disk space. There's no wrong answer, only a wrong surprise; now you've had both spoiled.

If your Desktop already emptied itself

Enabled it by accident and the Desktop looks bare? Nothing is deleted — the files moved one level, into iCloud Drive. Here's exactly where they went and how to bring them back.