How to uninstall SiYuan on Windows

SiYuan (思源笔记) is local-first: your notes live in a workspace folder you choose the first time you open it, and unless you set up SiYuan's own sync they exist nowhere else. Removing the app does not touch that folder, and this guide does not list or touch it either, so the main decision is yours: keep it for a reinstall, or copy it somewhere safe and delete it yourself. This guide covers SiYuan installed per-user from the B3log.SiYuan winget package.

Find your workspace first

Open SiYuan and check which folder it opened as your workspace; it is wherever you pointed it when you first set the app up. Copy that whole folder somewhere safe before you uninstall, since it is your only copy unless you turned on sync.

Quit SiYuan first

Quit SiYuan from its window or tray icon. SiYuan runs several processes for one window, so check Task Manager (Ctrl+Shift+Esc) for any SiYuan.exe still listed before you uninstall.

Remove the app with its own uninstaller

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

winget uninstall --id B3log.SiYuan

Where the data lives

Location	What it holds	What to do
Your workspace folder, wherever you chose it	Your notes, assets and workspace settings	Back it up; removing the app never touches it
`%APPDATA%\SiYuan-Electron`	The desktop shell's own settings, such as the data-storage and language choice from the welcome page	Safe to remove for a clean start

Check the result

Run these read-only commands after the uninstall finishes:

Get-Process SiYuan -ErrorAction SilentlyContinue
winget list --id B3log.SiYuan
Test-Path "$env:LOCALAPPDATA\Programs\SiYuan"
Test-Path "$env:APPDATA\SiYuan-Electron"

No output from Get-Process only means this query observed no matching process; a suppressed error leaves the running state unknown.
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\SiYuan-Electron" returning True means the desktop shell's settings are still there, which is expected unless you removed them yourself. Your workspace, wherever you put it, is separate and is never touched by this.

If you installed it with winget

winget uninstall runs the same NSIS uninstaller Settings › Apps uses and removes the same program files; it does not touch %APPDATA%\SiYuan-Electron or your workspace on its own.

What Mole lists

For SiYuan installed per-user from winget:

The program folder and the Start Menu shortcut are selected by default.
%APPDATA%\SiYuan-Electron is listed but not selected.
If a siyuan:// link registration still points at the removed program, Mole lists it too, selected by default, after backing it up to a .reg file.
Your workspace is never listed, since it lives in a folder you chose yourself.

What this test covered

Tested with SiYuan 3.8.5 installed through winget, per-user scope, opened once on the welcome page with data kept on the device. Not verified: a real workspace with notes, and SiYuan's own sync.