Moving folders · How moving folders works
What actually happens when Storage Studio moves a folder to my external drive?
Short answer: Storage Studio copies the folder's files to your external drive, checks the copy, removes the originals, and leaves links in their place so everything still opens from the same spot. It's a move, not a copy — nothing is stored twice.
The files are copied to your external drive, checked, and only then removed from your Mac — and a link is left in their place so everything still opens from the same spot. It's a move, not a copy: nothing ends up in two places, which is exactly why the space comes back.
Step by step
- Storage Studio copies the folder's contents to your fast drive.
- It checks the copy arrived complete before touching the original.
- It removes the original files from your built-in drive.
- It leaves links at the original place, so Finder, Spotlight and your apps still find everything where it was.
- It confirms each link really points at the copy on the drive.
The folder itself stays where it was; the files inside it become links. Everything moved this way can be moved back with one click from What's Using Space.
See also Can I undo a folder move?