DeepSeek Harness on Windows: Paths, Permissions, Terminals

Windows is not a different product

There is no official DeepSeek Harness desktop installer for Windows. DeepSeek Harness on Windows is still Node.js plus npx @deepseek-ai/dsh web, then a browser on http://127.0.0.1:3080/. The command matches the install checklist and the npx quickstart. What changes is the environment around it: which shell owns PATH, how Windows paths look to Git Bash or WSL, and whether Controlled Folder Access silently blocks agent writes.

This article is the Windows-only companion. If the process never binds or 3080 is taken, jump to the npx / port 3080 ladder instead of rereading OS one-liners.

Upstream still owns exact flags. When the official README disagrees with this page, the README wins.

Pick one shell and stick to its PATH

On the same PC you can open PowerShell, Windows Terminal (often PowerShell or cmd tabs), classic cmd, Git Bash, and WSL. Each can see a different node binary — or none.

1. Decide the shell you will use for the first hour. Prefer PowerShell or a Windows Terminal PowerShell tab for the documented path.
2. In that window only, run node -v and npm -v. Upstream preview expects Node ^22.19.0 or >=24.0.0.
3. If node is missing here but works in another app, your PATH is shell-specific. Fixing “the other window” does not fix this one.
4. Do not mix: install Node in PowerShell, then launch npx from a stale Git Bash session that still has Node 18 on PATH.

Git Bash is fine once PATH is correct, but path quoting and drive letters differ (D:\demo vs /d/demo). For first-run evaluation, stay in one shell until npx @deepseek-ai/dsh web prints a local URL.

Install Node so the same window sees it

1. Install Node LTS from nodejs.org or winget install OpenJS.NodeJS.LTS (see the Windows one-liner on Install).
2. Close and reopen the terminal — installers update user PATH; open tabs keep the old environment.
3. Confirm node -v is in range in the same shell you will use for npx.
4. cd into a disposable project folder (for example D:\scratch\dsh-demo), then run:

npx @deepseek-ai/dsh web

Keep the terminal open. Killing it stops the local server. Corporate proxies that MITM the npm registry look like product bugs; retry with the official registry when mirrors lag — details live on Troubleshoot.

Paths, workspaces, and Controlled Folder Access

The agent only sees the workspace root you select in the UI. On Windows that choice collides with everyday habits:

• Prefer a short path on a fixed drive (D:\scratch\...) over a deep tree under Documents synced by OneDrive on day one.
• Avoid pointing the first session at your entire user profile. Home folders mix secrets, mail caches, and cloud sync.
• Controlled Folder Access (Windows Security → Virus & threat protection → Ransomware protection) can allow the UI to open while tool writes fail or hang. If the agent “cannot write” with a healthy terminal, check whether your editor/Node process is allowed, or move the disposable repo outside protected folders for the first test.
• Execution Policy mostly affects PowerShell scripts you author — it rarely blocks npx itself. Do not set Bypass globally “just to try DSH.”

After the UI loads: paste a DeepSeek platform API key in settings, pick the disposable workspace, send a low-risk prompt (list top-level files). Local UI is usually a control plane, not offline weights.

Port 3080 and the browser on localhost

Default Web UI is loopback http://127.0.0.1:3080/. On Windows, find an occupant with:

netstat -ano | findstr :3080

Stop the PID in Task Manager or taskkill /PID <pid> /F, or start with the port flag documented upstream. First tests stay on localhost — binding 0.0.0.0 is a security decision. Blank page with a healthy terminal: try a clean browser profile; extensions sometimes block local scripts.

WSL is a second machine for PATH and files

WSL Ubuntu is not “Windows with a friendlier prompt.” Node installed on Windows does not automatically appear inside WSL, and vice versa. Keep the workspace on the Linux filesystem when you run DSH inside WSL — editing /mnt/c/... trees from Linux often adds permission and performance surprises. If you stay on native Windows PowerShell, do not also chase WSL Node versions in the same debugging session.

What this article is not

• Not a second full quickstart — narrative install stays in npx quickstart.
• Not a decision tree for every launch failure — use Fix npx and port 3080.
• Not an endorsement of unofficial “DeepSeek Harness Desktop” wrappers. Community launchers exist; they are optional skins around the same Node server.
• Not the macOS companion — Homebrew, TCC, and Full Disk Access live in DeepSeek Harness on macOS.

Where to go next

1. OS one-liners and verify steps: Install.
2. First-hour script: npx quickstart.
3. Symptom ladder: Troubleshoot and the port 3080 article.
4. After it runs, pick a mode before stacking community plugins.