Disk Map

Disk Map is a disk space analyzer for macOS, written in Swift, in the spirit of TreeSize. I wrote it because the space Finder reports as available is not all free. On my machine Finder said 7.25 TB was available, but only 1.14 TB could actually be written. The other 6.12 TB was purgeable content, such as iCloud files that can be evicted, caches and local snapshots, and Finder counted all of it as free.

Disk Map counts what a file really occupies on disk, not its apparent size. iCloud placeholders count as zero, because deleting them frees nothing, and a file with several hard links is counted once. Bytes that cannot be attributed to any file are listed with an explanation instead of being rounded away. On my 8 TB disk, which holds 11.6 million files, a full scan takes about 70 seconds and 0.7 GB of memory.

You can view the same scan as a treemap, a sunburst or an icicle chart, coloured by kind of file or by age. The Copies panel finds duplicate folders as well as duplicate files, including folders that are only partly the same. It compares names and sizes and reads no file contents, and when you want to be sure, Verify reads every byte of every copy. Nothing is deleted until you have seen a plan that shows, for each copy, which one stays and which goes to the Trash. Files go to the normal macOS Trash, so Finder's Put Back works on them.

The screenshots show a made-up folder tree, not a real disk, and the app renders them itself. Disk Map is open source under the MIT license, and you build it from source with Xcode.