You go looking for a file on your backup disk (a Pages document, a folder from Dropbox, that scan you filed away in iCloud Drive months ago) and it's nowhere to be found. The backup ran and it said it succeeded. So where did the file go?

Nine times out of ten, nothing is missing. The file is on the backup disk, just not where the Finder taught you to look for it. But be careful: depending on your setup, it's possible the files were not fully on your Mac to begin with. Let's untangle both scenarios.

Problem one: your cloud files live in a hidden folder

The "iCloud Drive" item in the Finder's sidebar is something of an illusion, for convenience. It isn't a plain folder, and the content inside it isn't laid out on disk like what you see on screen. The actual data is tucked away inside your hidden Library folder. An ordinary backup of your startup disk copies all of it faithfully — you just have to know the trick to finding it again on the backup volume.

To find cloud-hosted files on your backup disk:

1. Choose Computer from the Finder's Go menu
2. Select your backup disk, then navigate to Users > (yourname)
3. Press Command+Shift+Period to reveal hidden items
4. iCloud data lives in Library > Mobile Documents; everything else (Dropbox, OneDrive, Google Drive, Box) lives in Library > CloudStorage

Tired of toggling hidden files every time? Navigate to your home folder, press Command+J, and check Show Library Folder. Your next backup will carry that setting over, so the Library folder will be visible on the backup disk too.

iCloud Drive in particular plays an extra trick on you. It looks like one tidy folder, but it's actually a collection of folders in various places. None of these is a backup problem, exactly — it's just iCloud being iCloud.

Where each cloud service actually keeps your files

Problem two: some of those files aren't physically there

This is the one you want to watch out for. If your cloud storage is configured to save space by keeping some files "online only" — Apple's Optimize Mac Storage setting, and its equivalents in Dropbox and OneDrive — then those "evicted" files exist on your Mac as empty 0-byte placeholders with a little cloud badge next to the name.

CCC won't copy those empty placeholders, and that's deliberate: a 0-byte stand-in can't be meaningfully restored from a backup disk, so copying it would only give you a false sense of security. The real data is still safe in the cloud, of course. But "safe in the cloud" and "safe on a disk in my house" are two different kinds of safe, and if you want the second one, CCC can go get those files for you.

Setting up a dedicated cloud storage backup

1. Open CCC and click New Task; name it something like "Local Backup of Cloud Storage"
2. Click the Source selector and choose Cloud Storage
3. Click the Destination selector and choose a backup volume — if you're reusing the disk that already holds your startup disk backup, add a separate volume for it in the Backup Volume Setup Assistant
4. Click the Automation selector to put the task on a schedule, or click Start to run it right away

Choosing Cloud Storage as the source automatically turns on Temporarily download cloud-only files to make a local backup in Advanced Settings. With that enabled, CCC downloads the cloud-only files that need to be added to (or updated on) the backup, copies them, then evicts them again to reclaim the space — capping itself at roughly 100 files or 2GB of temporarily-downloaded content at a time so it never fills up your startup disk on the way through.

Why we recommend a separate volume

CCC normally works from a read-only snapshot of your source, which keeps a backup stable and internally consistent even while files are actively changing underneath it. Downloading cloud-only content breaks that model: to pull those files down, CCC has to write to your live, read/write startup disk. That's a perfectly reasonable tradeoff for a task scoped specifically to your cloud folders. It's not something we want imposed on the backup of your entire startup disk.

Keeping the cloud backup on its own volume also sidesteps a nastier problem down the road. If gigabytes of cloud-only content get folded into your startup disk backup, you can eventually find yourself unable to restore that backup to the original disk — because the data on the backup no longer fits on the Mac it came from. Discovering that on restore day is not the moment you want to learn it.

Photos needs a setting of its own

iCloud Photos doesn't use the cloud-only placeholder trick that the other services do. Instead it keeps optimized, low-resolution versions of your photos in the library — real files, with real content, that look completely ordinary to a backup app. CCC has no way to tell that what it's copying is a stand-in rather than the original.

So if you want full-resolution photos in your backup, tell Photos to keep them locally: turn on Download Originals to this Mac in Photos Settings > iCloud. Everything CCC copies after that is the real thing.

Sometimes it's the cloud, not you

Occasionally a cloud storage backup task starts reporting download errors and nothing about your setup has changed — because the problem isn't at your end at all. Before you start troubleshooting your Mac, spend thirty seconds on the provider's status page:

• Apple System Status (iCloud Drive)
• Microsoft 365 Service Health (OneDrive)
• Dropbox System Status
• Box Status
• Google Workspace Status Dashboard (Google Drive)

And while you're thinking about sync services behaving badly: a stalled or endlessly-running backup can also be a sign that a sync conflict has gone sideways, as one customer discovered when Dropbox spawned a million empty folders in his CloudStorage library.

Frequently asked questions

Where are iCloud Drive files stored on a Mac?

In your hidden Library folder, not in the sidebar location where the Finder shows them. Files you added to iCloud Drive yourself live in Library/Mobile Documents/com~apple~CloudDocs, and each app that stores documents in iCloud gets its own folder alongside it under Mobile Documents. Dropbox, OneDrive, Google Drive and Box all live under Library/CloudStorage instead. Press Command+Shift+Period in the Finder to reveal them.

Does backing up my startup disk also back up iCloud Drive?

It backs up everything that's physically present on the disk, which includes every cloud file that's fully downloaded. What it can't include are the files your Mac has evicted to save space — those are 0-byte placeholders, and a backup of a placeholder is still a placeholder.

Why are some of my cloud files 0 bytes on the backup?

They're 0 bytes on your Mac too. When a cloud service is set to optimize storage, it removes the local copy of files you haven't used lately and leaves behind a stub with a cloud badge. CCC deliberately skips those stubs rather than filling your backup with empty files that can't be restored.

Can CCC download cloud-only files so I get a real local backup?

Yes. Create a task with Cloud Storage as the source, which turns on Temporarily download cloud-only files to make a local backup automatically. CCC downloads the files it needs, copies them, then evicts them again — working in batches of roughly 100 files or 2GB so your startup disk never fills up in the process. Here are the steps.

Does CCC back up my iCloud photos at full resolution?

Only if Photos is keeping the full-resolution originals on your Mac. Unlike other cloud services, iCloud Photos stores optimized versions as ordinary files, so CCC can't distinguish a low-res stand-in from an original. Turn on Download Originals to this Mac in Photos Settings > iCloud if you want the originals in your backup.

Can I send my cloud storage backup to the same volume as my main backup?

We'd recommend a separate volume on the same disk instead — the Backup Volume Setup Assistant will add one for you. It keeps the read/write downloading behavior away from your startup disk backup, and it avoids bloating that backup with cloud content that may not fit back onto your Mac at restore time.

We're here to help

Cloud storage adds a layer of complexity that's genuinely confusing — even to us, some days. If you're not sure whether your cloud content is actually making it onto your backup disk, choose "Ask a question" from CCC's Help menu and we'll take a look with you. You can also read more about backing up the content of cloud storage volumes in the CCC Knowledge Base.