macOS processes › iCloud and sync
What is cloudd on Mac?
cloudd is the CloudKit daemon, the part of macOS that syncs app data with iCloud. Apple apps like Notes, Reminders, Messages and Safari, and many third-party apps, use it.
What it does
Apps don't talk to iCloud directly. They hand their changes to cloudd, which uploads them, fetches changes from your other devices, and keeps a local cache. Files in iCloud Drive go through a separate process called bird.
Why it gets busy
- An app syncing a lot of data, like a large Notes or Messages history after setup.
- Signing in to iCloud or setting up a new Mac, when everything syncs at once.
- A third-party app stuck in a sync loop.
- A slow or interrupted connection, which makes uploads retry.
Why is cloudd using so much CPU?
cloudd is syncing app data with iCloud. It's busiest after setup or sign-in and when an app has lots of changes. If it never stops, a third-party app stuck in a sync loop is a common cause.
Is it safe to quit?
macOS restarts it and syncing picks up where it left off, so quitting doesn't help.
How to calm it down
- Let the first sync after setup or sign-in finish, ideally on power and a fast connection.
- In System Settings › [your name] › iCloud, look at which apps sync and turn off ones you don't use on this Mac.
- Update third-party apps that use iCloud. A sync bug in one app can keep cloudd busy.
- Restart your Mac if cloudd stays busy for no clear reason.
In SystemWatch
SystemWatch labels cloudd as iCloud sync and knows its usual memory use, and the website edition also shows its network connections while it syncs.
