iCloud & iCloud Photos · Online-only files and Optimize Mac Storage
What does Store in iCloud in macOS storage settings do?
Short answer: It's a shortcut in System Settings → General → Storage that turns on iCloud syncing for Desktop and Documents and Optimize Mac Storage, so older files stay in iCloud. It uses your iCloud plan and needs a connection for online-only files.
It's a shortcut in System Settings → General → Storage that turns on iCloud features which move files to iCloud and let your Mac keep only what it needs — typically syncing Desktop and Documents to iCloud and using Optimize Mac Storage for iCloud Drive and Photos.
Before you click it, know what it changes:
- Your Desktop and Documents start syncing to iCloud and count against your iCloud plan.
- Older files can become online-only and need a connection to open.
If you'd rather not put everything in iCloud, you can keep files local and move big, non-synced folders to an external drive with Storage Studio instead. See Desktop & Documents in iCloud.