Free and open source · macOS 15 or later
See what’s filling your Mac. As it fills.
Silt scans your disk in seconds, then keeps a live, drillable tree of every folder as files come and go. When you’re ready to clear space, it tells you what’s safe and refuses to delete what isn’t.
Version 0.1.0 · Universal: Apple silicon and Intel · Notarized by Apple
Fast
Fast enough to leave open.
A whole developer folder, 1.3 million items, in under nine seconds. Then Silt stays current by re-reading only the folders that change.
Scanning ~/dev (1.3M items) on an M3 Max with other work running.
- ~55 MB
- for 1.2 million items, held in a flat, chunked tree
- 0.03%
- of a core while a quiet folder sits open
- Instant
- relaunch: the last scan loads straight back, then catches up
Features
Everything you need to get space back, and nothing you don’t.
A live, drillable tree
In the spirit of WinDirStat: every folder’s size, sorted, filling in while it scans and staying current as files change. Space for Quick Look, ⌘R to show in Finder.
Reclaim
Caches, build output (node_modules, Rust targets, DerivedData), installers and model weights, grouped and sized, with build output from projects you haven’t touched in months at the top.
Duplicates
Files with identical contents, compared by size, a sampled hash, then a full SHA-256. APFS clones already share their blocks, so they aren’t counted as waste.
What changed
“+2.8 GB since yesterday.” Silt compares against the last scan and shows the folders that grew or shrank most.
Sizes, precisely
Bytes on disk, counted once: hard links and clones are split between the files sharing them, and the space the volume reports but no scan can see is broken down too.
A cleanup basket
Mark anything as you go, then review it in one place, with a safety verdict on every item. Trash with Undo by default; deleting right away asks first.
Your pace
You decide how hard it works.
Most disk tools scan once and quit. Silt stays open and keeps watching, so it lets you choose how much of your Mac that’s worth.
Automatic
Scans you start run flat out. Keeping up with changes runs in the background, and everything eases off on battery, in Low Power Mode or when the Mac runs hot.
Fast
Everything at full priority, catching up included. Close a few apps and get the answer now.
Gentle
Low priority, on the efficiency cores, with slower disk access. Takes longer; you won’t notice it.
Paused
Silt does nothing on its own, but remembers what changed and catches up when you resume.
Busy folders slow down by themselves
A folder that never stops changing (agent logs, a build in progress) is updated less and less often, down to every 30 seconds. One you have open still updates every couple of seconds.
Rules for any folder
Right-click a folder to keep it live, update it slowly, pause it until you open it, or leave it out of the scan entirely.
Safety
Built not to delete the wrong thing.
A tool that frees space can also lose your work. Every destructive path in Silt checks again before it acts.
- Moves to the Trash by default, with Undo. Deleting right away always asks first.
- Never removes the last copy of a duplicate, and leaves a copy alone if it changed since the search.
- A mark is tied to the exact file it was made on. If that file is replaced, the mark is dropped.
- Won’t delete a volume mounted inside your scan, or system and home folders.
- Only calls build output “safe” inside your own projects, never inside an app or an installed tool.
- Tells you when a folder you marked has grown since, before you clear it.
Free, open source, and yours to keep.
MIT licensed and built in the open. If Silt got you some space back, you can buy me a coffee.
Version 0.1.0 · Requires macOS 15 or later