Underbrush privacy policy

Last updated: 22 October 2026

Underbrush is a desktop application for Windows and macOS published by LTC Labs. This policy covers what the application does with your data. The short version: your files, folder names and scan results never leave your computer.

What Underbrush stores on your computer

Data	Where it lives	Why
Settings	Windows %APPDATA%\LTCLabs\Underbrush\settings.json · Mac ~/Library/Application Support/LTCLabs/Underbrush/settings.json	Screen size and the choices below
History	Same folder, history.jsonl	The list of scans and clean-ups you see in the History tab, including the folders that were cleared
Diagnostic log	Windows %LOCALAPPDATA%\LTCLabs\Underbrush\Logs\ · Mac ~/Library/Logs/Underbrush/	Troubleshooting. Paths are removed as each line is written.
Support permission	%LOCALAPPDATA%\LTCLabs\Underbrush\ (Mac: the Application Support folder)	A signed permission from our server that lets this computer send support messages for the next day
Unsent crash reports and events	Same folder	Waiting to be sent if the computer was offline

What Underbrush sends to LTC Labs

Four kinds of data. None of them contain your files, file or folder names, scan results, or anything that identifies you. The optional ones can be turned off in Settings.

1. An update check. At most once a day, Underbrush sends a request to https://www.ltclabs.dev/api/app/update-check with the Underbrush version, your operating system and its version, an anonymous identifier for your computer, and a random ID that changes every time Underbrush starts. The identifier is a one-way hash, so it can't be turned back into anything about your computer and isn't linked to you. Our server also sees your IP address, as every web server does; we store only a hash of it and the approximate country. The check is on by default. Turn off Check for updates once a day in Settings to stop it.
2. Crash reports. If Underbrush crashes, it sends the error type, the error message, and the technical stack trace, with file and folder paths removed, along with the same version and anonymous identifier. On by default. Turn off Send crash reports to help fix bugs in Settings to stop it.
3. Diagnostic and usage events, sent in one batch to https://www.ltclabs.dev/api/app/telemetry when you close Underbrush (and every 30 minutes while it's open):
   • Always sent, so we can find and fix problems: Underbrush opened, Underbrush closed (and how long it was open), a scan failed, a clean-up failed (with a short error code, never the error text).
   • Usage data, on by default: a scan finished (how many files, how long it took, and the kind of drive), a clean-up finished (how many items, megabytes freed and set aside, how many were skipped), set-aside files were put back (how many files), a support message was sent, the help panel was opened, a help page was read (which page), a help search found something or nothing (the count only, never what you typed), the update link was clicked. Turn off Send anonymous usage data in Settings to stop these; any not yet sent are deleted.
   • The event names, for anyone checking: always sent app_launched, app_closed, scan_failed, clean_failed; usage data scan_completed, clean_completed, hold_restored, support_ticket_submitted, docs_opened, doc_panel_opened, doc_page_viewed, doc_search, doc_panel_contact_support_clicked, update_link_opened.
4. Support messages, only when you send one. From ? Help → Contact support…: the email address you type (shown back to you so you can catch a typo), an optional name, your subject and message, and:
   • if you leave Include diagnostic info checked: your Underbrush and operating system versions, the anonymous identifier, the session ID, the totals from your last scan (number of files, drive size and free space, the size of each pile; no names), and the last 500 lines of the diagnostic log, with paths removed. Larger logs are uploaded to our private support storage (Amazon S3) and linked to your ticket;
   • if you tick Attach a screenshot: a picture of Underbrush's own window only, never your desktop or other apps. It can show folder names from your scan, which is why it's off unless you choose it;
   • if you opened support from the Help panel: which screen you were on, the help page you last read, and what you searched for in Help.

Underbrush does not send file or folder names or paths, file contents, the results of your scans, or your clean-up history. It has no accounts and no advertising.

Children

Underbrush isn't directed at children and doesn't knowingly collect information from them.

Changes and contact

We'll update this page and its date if Underbrush starts handling data differently. Questions: [email protected].