Placeholder versus full download
With Optimize Mac Storage enabled, macOS may keep metadata and a cloud reference rather than every byte. Finder still knows the logical size, so the item looks complete while its local footprint can be tiny.
A cloud download icon usually indicates that the full content is not local. Recently opened items, files marked Keep Downloaded, and content macOS considers useful may have a local copy.
Why storage tools disagree
Some tools add logical file sizes, some read allocated filesystem blocks, and others separate purgeable content. Those definitions diverge sharply when iCloud, OneDrive, or Dropbox on-demand sync is heavily used.
Diskly focuses on the actual local footprint so an undownloaded cloud item is not presented as reclaimable local gigabytes. When comparing tools, check whether a total means logical, allocated, or on-disk size.
Safely remove a local copy
Confirm upload has completed, then use Remove Download in Finder for the file or folder. The local content is evicted while the cloud item remains available for a later download. Do not simply delete a file whose sync is incomplete: deletion can propagate to other devices.
Keep an independent backup for important work. Synchronization maintains a shared current state; it is not necessarily a complete, offline-restorable history.
Verify that space returned
Allow macOS time to reclaim blocks and refresh its totals. Watch actual free capacity, not only the size of the iCloud category. If files download again, an app may be accessing them or they may be marked Keep Downloaded.
For a large cloud library, periodically review the largest local folders instead of evicting every download at once.
Understand first, clean second
Diskly scans locally on your Mac, maps real usage in a treemap, and keeps every cleanup suggestion reviewable.
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