Back a Mac up to iCloud: what it covers and what Time Machine still needs

An iPhone has a button that says Back Up Now. A Mac does not, and hunting for the equivalent in System Settings is how most people arrive at this question. There is no Back Up This Mac switch in iCloud settings, and that absence is not an oversight or a feature waiting to ship. iCloud does something different from what the word backup implies, and the gap between the two is exactly where files get lost.

What follows separates the two ideas, then states what iCloud genuinely holds, what the storage costs today, and which job is left over.

Syncing and backing up are not the same job

A sync keeps one set of files identical across several devices. A backup keeps a second, separate copy of files as they were at a point in the past.

The difference shows up the moment something goes wrong rather than when everything is fine. Deleting a folder on a synced Mac deletes it everywhere, immediately, because propagating the change is the entire purpose of the system. Overwriting a document with a worse version syncs the worse version. A sync has no memory of yesterday to fall back on.

A backup does. Time Machine keeps hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all previous months. That history is the product. It is what allows a file to be recovered as it stood last Thursday, which a sync cannot do.

iCloud is a sync. It is a very good one, it does several jobs no local disk can do, and it is not a backup. Treating it as one is the single most common cause of a bad afternoon.

What turning on iCloud Drive actually moves

The setup is worth spelling out, because the second switch is the one that does the heavy lifting and it is easy to miss.

Open System Settings, click the name at the top of the sidebar, click iCloud, click Drive, then turn on "Sync this Mac". That connects iCloud Drive to the Mac. On its own it only covers files placed into iCloud Drive deliberately.

On the same screen is Desktop & Documents Folders. Turning that on moves the Desktop and Documents folders into iCloud Drive, which means files saved in the usual places are included without anything being dragged anywhere. After it is on, both folders appear in the iCloud section of the Finder sidebar, and in the Files app on an iPhone or iPad.

Apple attaches a warning to that switch worth reading twice. Any other cloud service that syncs those same folders should be turned off first, because two services working on the same folders interfere with each other and can stop the updating altogether. A Mac with Dropbox or another service pointed at the Desktop is the case this is aimed at.

A third switch, Optimize Mac Storage, lets the Mac keep older documents only in iCloud when local space is needed. When space is not needed, the full contents stay on the disk. This is genuinely useful on a small internal drive and it has a consequence: a file that exists only in iCloud is not a file that can be opened offline until it has been downloaded again.

Watching the sync without opening anything

Sync state is worth glancing at occasionally, and Apple documents a quick way to see it: hold the pointer over iCloud Drive in the Finder sidebar and click the status or information icon that appears.

That is a deliberate look, which means it will not happen often. Most people rely instead on whatever the menu bar shows them, and this is where Macs with several cloud services get into trouble.

The menu bar is a strip of fixed width. The left side carries the Apple menu and the menus of the app currently in front, and those take the room they need. The right side holds what Apple's documentation calls status menus, and every status icon competes for what remains. Two or three cloud clients, each with its own small icon and its own way of showing a problem, plus the built in controls, plus whatever else is installed, and the strip runs out. Items on the inner edge stop appearing, with no notice about which ones went.

The consequence is specific rather than cosmetic. A sync client showing an error badge that nobody can see is a sync client that has stopped for a week. The check that takes five seconds is to switch to the Finder, which has short menus, and see whether icons reappear that were absent a moment ago.

Where those icons are wanted but not all the time, the working arrangement is to keep them running and out of the visible strip, with a way to open them on demand. That is what a menu bar manager for macOS does, and the point here is narrow: an indicator only earns its space if it is still visible in the app being used.

What 5GB buys, and what the plans cost

Signing in to an Apple Account and turning on iCloud gives 5GB of free storage. That figure is per account, not per device, and it is shared.

Shared is the operative word. iCloud Drive draws on the same allowance as iCloud Photos, iPhone and iPad device backups, messages and attachments in iCloud Mail, and more besides. A single iPhone backup can consume most of 5GB on its own, which is why turning on Desktop & Documents Folders frequently produces an out of space message within a day.

Upgrading to iCloud+ is done in the same place. In System Settings, click the name at the top of the sidebar, click iCloud, then click Manage. The storage bar there shows current use broken down by category, clicking an app or feature shows what it is holding, and Change Storage Plan moves to a larger tier. These are Apple's published United States prices as of today.

Tier	Monthly price
iCloud, 5GB	Free
iCloud+, 50GB	$0.99
iCloud+, 200GB	$2.99
iCloud+, 2TB	$9.99
iCloud+, 6TB	$29.99
iCloud+, 12TB	$59.99

Prices differ by country and iCloud+ is not available everywhere. The same Manage screen offers Share with Family for anyone on an iCloud+ plan, with the note that in a Family Sharing group using one Apple Account for family purchases, the storage upgrade is billed to the family organiser.

What iCloud will not do, stated plainly

Three limits define the shape of the problem.

Time Machine cannot target iCloud. Apple's list of valid Time Machine destinations covers external drives connected to the Mac, partitions of those drives, and network attached storage reached over SMB. iCloud is not on that list and neither is an iPhone, an iPad, or a disk formatted for Windows. There is no configuration that turns iCloud into a Time Machine disk.

iCloud holds no system and no applications. What syncs is documents and data from apps that support it. The installed applications, the system itself, and the settings that make a Mac feel like a particular Mac are not in there.

And iCloud keeps no long history of a file's past states in the way a backup does. It keeps the current version, everywhere, quickly.

Set against that, iCloud does two things a local backup disk cannot. Files reach every signed in device and the web at iCloud.com, and they survive the physical loss of the Mac entirely, since a drive stolen along with a laptop protects nothing.

When iCloud runs out of room

Running out of iCloud storage does not behave like running out of disk space, and knowing the difference prevents a panic.

Apple describes the outcome precisely. If a document cannot be moved or saved to iCloud Drive, the storage is probably full. The document stays on the Mac and is uploaded to iCloud Drive once space becomes available. Nothing is thrown away. What is lost is the guarantee that the file exists anywhere other than the laptop, which is quietly the thing being paid for.

Two ways out exist, and the Manage screen in iCloud settings handles both. It is reached from System Settings by clicking the name at the top of the sidebar, clicking iCloud, then clicking Manage.

The first is to buy room, through Change Storage Plan on that screen.

The second is to clear room, and the same screen shows where it went. The storage bar at the top breaks usage down by category, and clicking any app or feature shows what it is holding. Two categories usually explain the whole picture.

Device backups are one. Clicking Backups lists iPhone and iPad backups stored in the account, and old backups belonging to devices that were replaced years ago sit there indefinitely. Deleting one frees its space, with the caveat Apple attaches: deleting the backup for a device still in use stops iCloud backing that device up automatically.

Per app data is the other. For many apps, clicking the app and choosing Delete from iCloud removes its documents and data. That removal reaches the Mac and every device that syncs with iCloud, so anything still wanted has to be copied out first. Some features, including Messages and iCloud Drive itself, do not offer that button, and the route for those is to turn the feature off in iCloud settings and delete items manually.

Photos deserves a look before either step, since a photo library is usually the largest single tenant in the account.

The split that works

The honest arrangement uses both, and assigns each a job it is actually good at.

iCloud Drive with Desktop & Documents Folders turned on covers reach and survival. Work in progress exists in more than one place, any device can pick it up, and a laptop that vanishes takes nothing irreplaceable with it. That case wants a storage tier large enough that it never silently stops, which is why the 5GB free tier is rarely the right answer once Desktop and Documents are included.

Time Machine to an external disk covers history and completeness. Apple's guidance on size is a factor rather than a number: use a disk with at least twice the storage capacity of the Mac, because the schedule keeps hourly, daily, and weekly history and starts deleting the oldest backups once the disk fills.

Neither one replaces the other, and neither is optional if the files matter. The failures they cover are different failures.

What to change first

Open iCloud settings and check whether Desktop & Documents Folders is actually on, because assuming it is covers nothing. Then look at the Manage screen to see whether the storage tier is large enough to hold what was just switched on, and make sure whatever reports sync trouble in the menu bar is still visible in the apps being used, which may mean clearing that strip down with Koffret first.