How to uninstall Jan on Windows

Everything Jan builds up lives in its data folder, %APPDATA%\Jan\data by default: downloaded models, your chat threads, assistants and extensions. Models can make that folder many gigabytes, and the uninstaller leaves it in place. If you plan to reinstall, keep the folder, or move the models and threads you want to another drive, before you remove anything. If you changed the location in Settings › General › Jan Data Folder, your data is there instead, and that folder needs the same decision. This guide covers Jan installed per-user from the Jan.Jan winget package. Jan data folder

Stop the model server and quit Jan

Jan runs local models through a separate llama-server.exe, started from %APPDATA%\Jan\data\llamacpp. In this test that server kept running after Jan's window closed and even after the uninstall finished, holding the data folder open. Stop any running model in Jan, quit the app, then open Task Manager (Ctrl+Shift+Esc) and end any Jan.exe or llama-server.exe still listed. The test found no startup entry.

Remove the app with its own uninstaller

Go to Settings › Apps › Installed apps, find Jan, and choose Uninstall, or run:

winget uninstall --id Jan.Jan

The uninstaller removes the program folder in %LOCALAPPDATA%\Programs\Jan. It does not touch %APPDATA%\Jan.

Where the data lives

Location	What it holds	What to do
`%APPDATA%\Jan`	`data` with downloaded models (`llamacpp\models`), chat threads, assistants, extensions and logs, plus `settings.json`	Keep it, or copy the threads and models you want elsewhere, if you might reinstall; remove it only when you no longer need them
`%LOCALAPPDATA%\jan.ai.app`	The embedded browser's data and cookies	Safe to remove for a clean start
`%APPDATA%\jan.ai.app`	A small updater file	Safe to remove
`HKCU\Software\Menlo Research Pte. Ltd.\Jan`	A small settings key the uninstaller left	Safe to remove once the app is gone

The PATH entry

In this test Jan's installer added %LOCALAPPDATA%\Programs\Jan\resources\bin to your user PATH, and the uninstaller left that entry pointing at a folder that no longer exists. It does no harm, but you can remove it in Settings › System › About › Advanced system settings › Environment Variables, under your user's Path.

Check the result

Run these read-only commands after the uninstall finishes:

Get-Process Jan, llama-server -ErrorAction SilentlyContinue
winget list --id Jan.Jan
Test-Path "$env:LOCALAPPDATA\Programs\Jan"
Test-Path "$env:APPDATA\Jan"
Test-Path "HKCU:\Software\Menlo Research Pte. Ltd.\Jan"
[Environment]::GetEnvironmentVariable("Path", "User") -split ";" | Select-String "Programs\\Jan"

No output from Get-Process only means this query observed no matching process; a suppressed error leaves the running state unknown. A listed llama-server means the server is still holding the data folder; end it in Task Manager.
A completed winget list query with no match means the package record is gone; a matching row means the uninstall did not finish.
The first Test-Path returning False means the program folder is gone; True means files remain there.
Test-Path "$env:APPDATA\Jan" returning True means your models and threads are still on disk, which is expected if you kept them. False means they are gone.
The registry Test-Path returning True means the settings key is still there; False means it is gone.
The last command printing a line means the PATH entry is still there. No matching output from a confirmed successful query means it was removed.

If you installed it with winget

winget uninstall runs the same uninstaller Settings › Apps uses and removes the same program files; it does not touch %APPDATA%\Jan, the two jan.ai.app folders, the settings key or the PATH entry.

What Windows apps leave after uninstalling also covers leftover data and background processes.

What Mole lists

For Jan installed per-user from winget:

The program folder goes with the app row.
The desktop and Start Menu shortcuts and a row grouping Windows' own records of when you opened the program are selected by default.
%APPDATA%\Jan, %LOCALAPPDATA%\jan.ai.app and %APPDATA%\jan.ai.app are listed but not selected. Ticking %APPDATA%\Jan, yourself or with Also remove data, sends your models and threads to the Recycle Bin with it, and a large models folder may be too big for the Recycle Bin, in which case Windows asks before deleting it for good.
HKCU\Software\Menlo Research Pte. Ltd.\Jan is listed but not selected, and is backed up to a .reg file before removal.
When Jan goes, Mole names a llama-server.exe still running from Jan's data folder among the running apps and quits it, even when you keep the data folder. Nothing in the folder is removed by that.
The PATH entry is not listed; check it with the command above.

What this test covered

Tested on September 29, 2026 with Jan 0.8.4 installed through winget, per-user scope, from an elevated session, on an ARM64 virtual machine. The uninstaller is NSIS and ran silently. Every listed row was ticked; the test did not go through Mole's running-apps prompt, so llama-server.exe kept running from %APPDATA%\Jan\data\llamacpp and that folder could not go to the Recycle Bin. Every other listed row was removed. No model was downloaded and no chat was started, so moving or removing a large model library was not verified.