UndigDeleted files but disk space didn’t free up? 4 reasons (and fixes)
You deleted gigabytes and your Mac’s free space didn’t change. Here are the four real reasons on macOS, and how to check each one.
You deleted 20 GB, emptied the Trash, and the free space barely moved. It is one of the most common Mac complaints, and it almost always comes down to one of four causes.
1. The Trash isn’t empty
Moving a file to the Trash doesn’t free its space: it still sits on your disk until you empty the Trash. Cleaners that “remove” items to the Trash have the same limit.
2. An app still has the file open
On macOS, a deleted file keeps its space for as long as a running program holds it open. Docker, Xcode, dev servers and apps writing big logs do this a lot. Quitting or restarting the app releases the space.
To see it yourself, run this in Terminal. It lists open files that no longer exist on disk:
lsof +L13. A local snapshot keeps the old version
Time Machine (and macOS updates) create local APFS snapshots. A snapshot preserves the old state of your disk, including files you deleted since. macOS removes them on its own, usually within 24 hours or when space runs low. To list them:
tmutil listlocalsnapshots /To ask macOS to thin them now:
sudo tmutil thinlocalsnapshots / 100000000000 44. Clones and purgeable space
APFS clones share their data blocks with the original, so deleting one frees almost nothing. And “purgeable” space is counted as available by macOS, but only given back when needed, so the numbers can look different from one screen to another.
Undig’s Ghost Space compares what you expected to free with what you really freed after emptying the Trash. If there is a gap, it shows which app holds deleted files, lists your snapshots and the purgeable space, and tells you what to quit. See also what “System Data” really is.