iCloud files show up in Finder but won't open when you're offline — they got silently removed from your Mac
You can see the file right there in Finder, you double-click it, and nothing. Or you get a spinning wheel and an error. Turns out the file isn't actually on your Mac anymore — it's in the cloud and you're on a plane with no Wi-Fi.
Why does this happen?
When Optimize Mac Storage is enabled, macOS automatically evicts local copies of iCloud files to free up disk space, replacing them with lightweight placeholders shown with a cloud icon. The files look present but aren't — they need to be re-downloaded on demand.
How to fix it
To keep a file always available offline: right-click it in Finder → Download Now or Keep Downloaded.
To disable optimize storage entirely: System Settings → Apple ID → iCloud → uncheck Optimize Mac Storage.
Look for the small cloud icon next to a file in Finder — that means it's not stored locally.
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