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What is the bird process on a Mac? iCloud Drive's sync engine, explained

bird syncs iCloud Drive. High CPU or disk use from it means a sync is running or stuck. On our Mac it sat at 0% with 6 MB. How to check and restart it.

4 min read

What is bird?

bird is the iCloud Drive daemon: it uploads, downloads and tracks every file in iCloud Drive, including Desktop and Documents when those sync. It lives in /System/Library/PrivateFrameworks/iCloudDriveCore.framework and runs as you.

On our Mac it had run for 43 minutes at 0.0% CPU with 6 MB of memory: nothing to sync.

Why is bird using so much CPU?

  • Many files changed at once in iCloud Drive, or Desktop and Documents were just turned on.
  • Files are being downloaded because you opened them, or evicted because space is low.
  • A sync is stuck, usually on one file: very large, oddly named, or in use.

How do I check and fix it?

Look at iCloud Drive in Finder's sidebar: a progress circle means it is working. If it is stuck for hours, restart the sync engine; macOS starts it again straight away:

killall bird

Keeping project folders, with their thousands of small files, out of iCloud Drive is the lasting fix for most bird complaints. See iCloud Drive taking up space and turning off Desktop and Documents sync.

See it live

Free Mac's System tab ranks every process by processor use and energy impact, once a second, and marks the ones macOS will not let you quit as protected. See also cloudd and fileproviderd.

Related: cloudd and nsurlsessiond.

Common questions

What is the bird process on a Mac?

The iCloud Drive daemon, which syncs every file in iCloud Drive. It is part of macOS, not malware.

Why is bird using so much CPU?

It is syncing many files, or stuck on one. Check iCloud Drive in Finder's sidebar for progress.

Is it safe to kill bird?

Yes. macOS restarts it immediately and the sync carries on.

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