Why deleting files doesn't always give the space back

You delete or move a large folder and your free space barely changes, or even goes down. Nothing is broken: the space is usually still being held somewhere for a while. There are three common reasons, and Storage Studio can show you which one is at work.

1. It's in the Trash

Deleting a file in Finder moves it to the Trash, and it keeps using space until the Trash is emptied. Storage Studio shows how much your Trash is holding (in Storage Inspector and Emergency Space), but leaves the decision to empty it to you, because that can't be undone. See The Trash and the space it holds.

2. Your Mac's automatic backups are holding it

This is the one that surprises people most. Your Mac takes local snapshots, automatic backups of the disk. A snapshot keeps every file that existed when it was taken, so when you delete or move a file afterwards, the snapshot still holds its blocks until the snapshot itself goes. Deleting more files won't bring that space back; only letting go of old snapshots does.

macOS counts much of this space as purgeable: it will free it on its own when it needs room, usually within a day. That's why two "free space" figures can disagree. Some screens count the held space as free; the space you can actually use right now is smaller. Storage Studio says so where it matters, for example in the What changed in this period breakdown under the storage chart.

What Storage Studio does about it:

• Storage Inspector shows a Pinned figure and a Space held by backups section, with the age of each snapshot.
• When a drop in free space is mostly held space, the notice says Your free space will come back on its own and, when there's enough held, offers Release that space.
• Emergency Space puts Release space held by automatic backups first, because it returns space without deleting anything you still have.
• The Local Snapshots screen lets you remove snapshots yourself. See Local snapshots.
• After a Smart Care run that moved files, the summary warns you if your Mac may hold on to that space for a little while.

%% caption: Why free space can stay the same after a file is deleted
flowchart TD
  A[You delete or move a big file] --> B{Is it in the Trash?}
  B -->|Yes| C[Space returns when the Trash is emptied]
  B -->|No| D{Did a local snapshot exist before?}
  D -->|Yes| E[Snapshot holds the space until it is released]
  D -->|No| F{Does an app still have it open?}
  F -->|Yes| G[Space returns when the app lets go]
  F -->|No| H[Space is free now]
  E --> I[Release it from Storage Studio, or wait for macOS]

3. An app is still using it

A file that an app has open is in use. Storage Studio won't move or clear anything an app has open, and when you move a folder from Storage Inspector it lists the apps using it, with Quit and Quit all buttons. Quitting the app is usually all it takes. See When an app is holding a folder open.

How to check

Open the More menu (•••) → Where Did My Space Go… and select the period on the chart. The breakdown lists the space held in automatic backups as its own line, separately from files that really grew. See Where did my space go?.

See also: I moved files but my free space didn't go up · Storage Studio and Time Machine · Purgeable space