You deleted files but free space didn't change: here's the fix

You emptied the Trash. You dragged a 20 GB folder of old video off the disk and moved a couple of big apps out too, and Storage settings barely moved. If you're deleting files but not freeing space on your Mac, you're not imagining it: on an APFS disk, the space you delete and the space macOS reports back are often on a delay, and a few things quietly keep holding the blocks after the file is "gone." Here's the ordered checklist, real causes first, with the fix for each.

Why deleting files isn't freeing space on your Mac

On APFS, "deleted" doesn't always mean "space returned this second." Something is usually still referencing those blocks, or macOS is reporting a number it hasn't caught up on yet. Work down this list in order. The first one or two fixes clear it the vast majority of the time. (For the deeper reason the numbers you see can't be trusted in the first place, see why your Mac lies about free space.)

1. The Trash you didn't fully empty

The simplest culprit, and the easiest to miss. Dragging a file to the Trash frees nothing. The space isn't returned until you empty it (Finder → Empty Trash, or turn on Empty Trash Automatically in Storage settings to clear anything older than 30 days).

But there's rarely just one trash:

• Photos keeps deleted shots in a Recently Deleted album for around 30 days before they're gone for good. Open Photos → Recently Deleted in the sidebar → Delete All.
• Mail moves deleted messages to a Trash mailbox and keeps them until you erase it (Mailbox → Erase Deleted Items).
• Some apps keep their own internal trash or library that a normal delete doesn't touch.
• External and second drives have their own separate Trash. Emptying the boot disk's Trash doesn't clear theirs.

Empty each of these, then re-check your free space.

2. A local APFS snapshot is still holding the blocks

This is the big one. When Time Machine or a macOS update takes a local snapshot, APFS retains the original blocks of anything you change or delete afterward, for as long as that snapshot exists. The file is gone from Finder, but its blocks are pinned until the snapshot is thinned.

macOS is meant to clean this up on its own: snapshots older than 24 hours are deleted automatically, and more get removed when the disk runs low. You can see what's currently on your boot volume:

tmutil listlocalsnapshots /

The safe move is simply to wait. The space usually comes back within a day, faster if you're low on room. If you need it back sooner, you can thin the snapshots yourself, but that touches Time Machine's local restore points, so do it deliberately. The how-to (and when it's worth it) is in Time Machine local snapshots.

3. The space went "purgeable," not free

Sometimes the space you freed doesn't show as free. It shows as purgeable. That's Apple's term for storage macOS will release on demand when it needs the room. You can't delete it yourself and there's no button for it; only macOS can.

So don't chase it. The fix is indirect. Free up real space (empty the Trash, delete large files you don't need, clear the caches you actually own in ~/Library/Caches), and macOS reclaims purgeable space on its own when the disk gets tight, usually within minutes. What counts as purgeable (and why even experts disagree on it) is in purgeable space on a Mac.

4. iCloud "Optimize Storage" is re-filling the space

If Store in iCloud / Optimise Mac Storage is switched on (for Photos, or Desktop & Documents), macOS, not you, decides what stays on the disk. Two things can mask your delete: a sync may still be mid-flight, or, precisely because you just freed room, macOS may pull down full-resolution originals it had offloaded to keep more of them local, quietly using the space back.

Let iCloud finish syncing before you judge the number. Watch the status in the Finder sidebar or at the bottom of the Photos window. And remember that with Optimize Storage on, the amount kept locally is macOS's call, not a fixed total, so it will drift on its own.

5. Finder is just showing a stale number

Finally, the delete may have worked and Finder simply hasn't caught up. Its free-space figure is frequently wrong and slow to refresh. It folds in purgeable space it may not actually be able to deliver.

Don't trust it for this. Read the real number instead:

• Disk Utility: open it, and in the sidebar select the APFS container (the top-level item, not the volume nested under it). That figure is the filesystem's own accounting.
• Terminal, if you prefer: df -h / and read the Avail column.

A restart also forces macOS to recompute the number, which alone resolves a surprising number of "it didn't change" reports.

What usually did it

Most of the time it's the first two: a trash you didn't fully empty, then a snapshot that hasn't thinned yet. Work down the list and re-check the real free space in Disk Utility, not Finder, after each step, so you can tell which fix actually moved the needle.

That last part is the tedious bit. You delete something, the number doesn't budge, and you can't tell whether it worked or macOS is just holding the blocks. That's the gap Plumby closes. It counts the bytes it actually removes, so you see what really went instead of Finder's guess, names the exact paths it clears, and acts only on your command, never touching your documents, photos, or projects.