Getting started

Last updated: 22 October 2026

Scan your drive

Pick a drive in the box at the top left. Underbrush lists your fixed drives (on a Mac, "Macintosh HD") and your Home folder. Scanning the home folder is quicker if you only care about your own files.
Press Scan. The counter shows how many files it has looked at. A full drive with a couple of million files takes about half a minute to a few minutes. Press Stop to cancel.
Read the Dashboard. It shows how much is free, a bar split into piles, and the folders at the top of the drive, biggest first. See Dashboard.

Scanning only reads. Nothing changes on your drive until you clear something.

The quick way:

On the Dashboard, press Free up …. It only covers the Safe to clear pile: caches, temp folders and build leftovers that rebuild on their own.
Underbrush shows the total and how many places it will clear. Press Clear now, or Cancel.
When it's done it shows how much was freed and how free space changed.

The careful way:

Click See the list (or open the Clean up tab).
Untick anything you want to keep, and tick anything from Your call you want gone.
Press Review and clear, read the list, then press Clear.

Deleted means deleted. Underbrush doesn't move things to the Recycle Bin or Trash. Everything in Safe to clear is something apps rebuild or re-download.
Recent files are skipped. Anything written in the last 3 days stays, so caches in use keep working. See The piles and the safety rules.
Too small or too big? Press Ctrl + / Ctrl − (Cmd on Mac), or use the − and + at the top right. Ctrl 0 resets. Underbrush picks a size for your screen the first time and remembers what you choose.
Every scan and clean-up is logged in the History tab.

Still stuck? In the app, use Help → Contact support, or open a ticket here.