Check it. Test it. Block it if you want.
Larch is an on-device meeting transcriber for Windows from Belted Labs LLC. This page is everything it does on a PC, what it stores, the one network call it makes, and how to remove or block it. Print it as a PDF for your review.
1What it does
Larch runs in the Windows tray. When a Teams, Zoom or Google Meet (Chrome or Edge) call starts, it records the user’s microphone and the meeting app’s audio, writes a speaker-labeled transcript to a folder on the PC, and deletes the audio. Speech recognition (whisper.cpp) and speaker labeling (sherpa-onnx) run inside the Larch process.
2Data path
Sound in
Mic, as “Me”.
Meeting app audio only (WASAPI process loopback).
Larchper-user process
Temp audio encrypted with DPAPI. Speech to text and speaker labels. Writes the file, deletes the audio.
User’s folder
One .md per meeting, plain text. Default Documents\Meetings.
3Network
One destination, the update host. Blocking it stops updates and license renewal; recording keeps working until the key expires. No account, no sign-in, no telemetry of meeting content.
Check: if the user’s folder is synced (OneDrive Known Folder Move), the transcript syncs with it. That’s your sync policy, not Larch.
4Install
Per-user installer under %LOCALAPPDATA%. No admin rights, no service, no driver. Signed by Belted Labs LLC (OV certificate, timestamped). The installer is about {size}: the speech models are inside, so nothing downloads on first run. Starts at login by default. Updates install when the user quits Larch, never during a call. Windows 11.
5What’s stored, and for how long
- Meeting audio
- Encrypted to the user’s account (DPAPI), deleted once the transcript is saved; if transcription fails it’s kept and retried.
- Transcripts
- Plain Markdown in the chosen folder until the user deletes them.
- Voice data
- Speaker embeddings in memory for one meeting, never written to disk or reused.
- Settings
%APPDATA%\Larch\settings.json
To spot meetings, Larch reads the Windows mic-in-use records, the process list and browser window titles, all on the PC.
6Recording behavior: read this first
Larch starts recording on its own when a supported meeting app takes the mic, with no prompt. It doesn’t join the call or post anything, so other participants aren’t told unless the user tells them. The tray icon barely changes while recording; the true state is in the tooltip. Larch’s own windows are excluded from screen capture. Larch doesn’t handle consent. Users are responsible for recording laws, including all-party-consent states, and for your policies.
7How to block it
App Control for Business or AppLocker: a publisher rule on the Belted Labs LLC certificate, or a hash or path rule on the Larch executable. Rules that block apps in writable user folders (CISA CM0101) block Larch. Blocking the update host stops updates and renewals only.
8How to remove it
Settings > Apps > Installed apps > Larch > Uninstall. No admin needed. Transcripts are the user’s files and stay in their folder; delete them separately if your policy requires. Check %LOCALAPPDATA%\Larch\ and %APPDATA%\Larch\ for leftovers.
9What Belted Labs holds
Purchaser email, Stripe billing records, license records and update-check logs. Never meeting audio, transcripts, titles, names or voice data.
10Contact
Questions about Larch for your team: {support}.