How to Set Up iCloud Drive on Mac and iPhone So It Doesn't Eat Your Storage
A practical guide to setting up iCloud Drive on Mac and iPhone without filling up your local disk or your iCloud+ plan. Exact paths, recommended settings and common mistakes.
iCloud Drive is one of those Apple features that, when set up properly, saves you a lot of headaches. Set up badly, it fills the SSD of your MacBook Air M3 in an afternoon or leaves you unable to take a photo because “there’s no space in iCloud”. Let’s get it right.
This guide applies to macOS Sequoia 15.x and iOS 18.x (also iPadOS 18). If you’re on an older version, most of the paths still work, but some menu names change. Estimated time: 20-30 minutes if you take it slowly.
What iCloud Drive is and how it differs from iCloud
First, let’s clear up the terminology, because Apple mixes it up and confuses people.
iCloud is the umbrella: it includes iPhone backup, iCloud Photos, Contacts, Calendars, Notes, Keychain, iCloud Messages, etc. All of that takes up space in your plan.
iCloud Drive is just one part: the cloud file system. It’s where the folders you see in the Files app on iPhone or in the Finder sidebar live. This is where Pages documents, PDFs, your own folders end up and—if you turn it on—the Mac’s Desktop and Documents.
The difference matters because you can turn off iCloud Drive without losing Photos, and you can turn off iCloud Photos without losing your iCloud Drive files. They are independent modules.
Prerequisites
- An Apple Account (formerly Apple ID) signed in on your Mac and iPhone.
- macOS Sequoia 15.1 or later on the Mac (Apple menu → About This Mac).
- iOS 18.1 or later on the iPhone (Settings → General → About).
- An iCloud+ plan if you’re going to move more than 5 GB. The current plans in Spain are: 50 GB for €0.99/month, 200 GB for €2.99/month, 2 TB for €9.99/month, 6 TB for €29.99/month and 12 TB for €59.99/month.
- A stable Wi-Fi connection for the first sync.
How to turn on iCloud Drive on Mac, step by step
- Open System Settings (Apple menu → System Settings).
- Click your name at the top left.
- Go to iCloud.
- Click Drive.
- Turn on Sync this Mac.
- In the list of apps below, decide which ones use iCloud Drive (Pages, Numbers, Keynote, Preview, etc.).
You’ll also see a switch called Desktop & Documents Folders. Be careful with this one, since it’s the one that usually blows up iCloud accounts. We’ll look at it in its own section below.
How to turn on iCloud Drive on iPhone, step by step
- Open Settings.
- Tap your name at the top.
- Go to iCloud.
- Tap Drive (under “Saved to iCloud”).
- Turn on Sync this iPhone.
From here on, the Files app already shows iCloud Drive in the “Browse” tab. If you drag a PDF there, it appears in the Mac’s Finder within seconds.
Optimize Storage on Mac: the key option
This is the setting that makes the difference between “iCloud Drive works for me” and “iCloud Drive has filled my disk”.
Path: System Settings → [your name] → iCloud → Drive → Optimize Mac Storage.
With this option on, macOS keeps only recent files or files you open often. The rest are downloaded on demand when you double-click them. You’ll see them in the Finder with a cloud icon next to the name.
When to turn it on? Whenever your iCloud Drive takes up more space than you have left on the SSD. If you have a 256 GB MacBook Air M3 and 400 GB in the cloud, there’s no debate: turn it on.
When to turn it off? If you travel a lot without decent Wi-Fi and need every file locally, always. In that case, consider an external SSD for heavy files instead.
Desktop & Documents in iCloud: when yes and when no
When you turn on Desktop & Documents Folders, macOS uploads the contents of those two folders to iCloud Drive. Convenient: you open your iPhone and see your Mac’s desktop files. Dangerous: if your desktop holds 80 GB of material and your plan is 50 GB, sync gets blocked and fills the cloud.
Turn it on if:
- You work with several Macs and want the same desktop on all of them.
- You have a 200 GB plan or more.
- Your Desktop and Documents don’t exceed 50% of your iCloud quota.
Don’t turn it on if:
- You use the desktop as a graveyard for downloads and screenshots.
- You have video projects or Xcode projects in Documents. Those folders blow up any plan.
- You share the Mac with other user accounts.
If you already turned it on and regret it, go to System Settings → [your name] → iCloud → Drive, turn off Desktop & Documents Folders and macOS will warn you: the files stay in iCloud, and new, empty Desktop and Documents folders appear on the Mac. Manually move whatever you want to keep locally from the Finder sidebar (iCloud section) into the new local folder.
Optimize Storage on iPhone
In iOS 18, the Files app also downloads on demand by default. Files with a cloud icon are in iCloud; those without are local.
To check it: Settings → General → iPhone Storage. There you can see which apps take up what. Scroll down until you see Files and check how much it stores locally.
If you want to free up space, in the Files app press and hold a downloaded file or folder and choose Remove Download. It stays in iCloud and leaves the iPhone.
A little-known tip: Messages can also eat your plan. In Settings → [your name] → iCloud → See All → Messages in iCloud you can turn it off if you don’t mind losing your message history across devices. Sorry, iMessage history.
Managing your plan and seeing what takes up space
Quick path: Settings → [your name] → iCloud → Manage Account Storage (on Mac: System Settings → [your name] → iCloud → Manage).
There you’ll see a breakdown by category: Backup, Photos, Drive, Messages, Mail, WhatsApp… If WhatsApp takes up 40 GB, you know where to cut back.
To change plans: Change Storage Plan. Upgrading is immediate; downgrading takes effect at the end of the monthly cycle.
Common problems
“iCloud Drive isn’t syncing”. Check that you’re signed in with the same Apple Account on both devices (Settings → [your name]). Make sure iCloud Drive is on on both. Force a sync by leaving the Mac awake on Wi-Fi for 10-15 minutes. On iPhone, close the Files app and reopen it.
“There’s no space left in iCloud” with the plan mostly empty. This is usually an old backup from an iPhone you no longer use. Go to Manage Storage → Backups and delete it.
Files show a cloud icon and won’t download. Tap the icon to force the download. If it takes too long, check that Low Power Mode isn’t on (iPhone) or that “Mobile Data” isn’t restricted for Files.
Desktop full of cloud-icon files I can’t open offline. Select the ones you want always available, right-click → Download Now. They get marked as local.
The Mac says “This Mac is full” but iCloud says there’s space. That’s your local SSD, not the cloud. Turn on Optimize Mac Storage and empty Downloads and the Trash.
Alternatives to iCloud Drive
If your usage is heavy (video projects, RAW photos, code), iCloud Drive isn’t always the best tool.
- Dropbox and Google Drive work better with files edited collaboratively in real time.
- OneDrive comes free with Microsoft 365 (1 TB for €69/year, Personal plan) and integrates decently with Finder.
- For heavy files you don’t need to sync, an external SSD like the Samsung T9 or Crucial X10 Pro is more cost-effective in the long run than upgrading your iCloud plan to 2 TB.
Nothing stops you from combining them: iCloud Drive for light documents and sync with iPhone, an external SSD for raw material, Dropbox for working with clients.
Frequently asked questions
If I turn off iCloud Drive on the Mac, are the files deleted? No, it asks whether you want to keep a local copy. Choose “Keep a Copy” and they appear in your user folder inside a folder called iCloud Drive (Archive).
Can I have iCloud Drive on on the Mac but off on the iPhone? Yes. These are independent settings per device. Each one decides whether to sync or not.
Do files I delete from the Mac also get deleted from iCloud? Yes, if iCloud Drive is on. They go to the iCloud trash for 30 days, so you can recover them from iCloud.com → Account Settings → Restore Files.
How long does the first sync of Desktop and Documents take? It depends on the size and your connection. For 50 GB on decent fiber, expect several hours. Leave it plugged in and on Wi-Fi.
Does iCloud Drive work on Windows? Yes, with the iCloud app for Windows from the Microsoft Store. It integrates iCloud Drive into File Explorer. It’s not as polished as on Mac, but it does the job.
Can I share iCloud Drive folders with other people? Yes. Right-click the folder → Share → Collaborate. You can grant read-only or edit permission, and decide whether anyone with the link can join or only invited people.
