Moving folders · How moving folders works
What is the shortcut Storage Studio leaves behind after a move?
Short answer: It's a small link at the original location that points to the file's new home on your fast drive. Apps and macOS follow it automatically, so files open from the same place while the drive is connected, and the link itself uses almost no space.
It's a small link at the original location that points to the file's new home on your fast drive. Apps and macOS follow it automatically, so a file opens exactly where it did before — the data just lives on the external drive now.
A link takes up almost no space, which is why moving a large folder frees nearly all of its size. Because the link sits at the same path as the original file, anything that refers to that path — a project, a script, a recent-files list — keeps working while the drive is connected.
If the drive is unplugged, the links have nothing to point to until you reconnect it. See what happens when the drive is unplugged.