# Fix "spawn npx ENOENT" in MCP Servers: Claude Desktop, Cursor & Windows

> spawn npx ENOENT means your MCP client couldn't find npx, not that your server is broken. Here's why it works in your terminal but fails in Claude Desktop or Cursor, and the exact config fixes for macOS, Windows, uvx and docker.

**Source:** https://mcpplaygroundonline.com/blog/fix-spawn-npx-enoent-mcp  
**Author:** Nikhil Tiwari  
**Published:** 2026-10-28  
**Category:** Troubleshooting  
**Reading time:** 9 min read  
**Topics:** spawn npx ENOENT, spawn npx ENOENT claude desktop, spawn npx ENOENT windows, spawn uvx ENOENT, MCP server spawn ENOENT, env: node: No such file or directory MCP, claude desktop npx not found, cursor MCP spawn npx ENOENT, MCP server not starting, spawn EINVAL npx.cmd

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📖 TL;DR

-   **`spawn npx ENOENT` means the MCP client could not find the `npx` program.** Your server code never ran.
-   **On a Mac**, apps opened from the Dock get a short PATH (`/usr/bin:/bin:/usr/sbin:/sbin`) that leaves out Homebrew, nvm, Volta and uv. Fix it with an absolute path _and_ a `PATH` in the server's `env`.
-   **On Windows**, `npx` is really `npx.cmd`, which Node can't start directly. Use `"command": "cmd"` with `"/c", "npx"` at the start of `args`.
-   **Everywhere**, put only the program in `command`. `"npx -y some-server"` in one string fails with the same error.
-   Running the server from your terminal hides the bug, because the terminal has the full PATH. Test it in an app opened the same way as your MCP client.

## Table of Contents

-   [What "spawn npx ENOENT" means](#what-it-means)
-   [Find your exact error](#which-one)
-   [Where to find the error](#logs)
-   [Fix on macOS: absolute path plus PATH](#fix-mac)
-   [Fix on Windows: cmd /c npx](#fix-windows)
-   [Fix everywhere: one program in "command"](#fix-command)
-   [Same error for uvx, node, python and docker](#uvx-docker)
-   [Check the fix before you restart the client](#verify)
-   [FAQ](#faq)

## What "spawn npx ENOENT" means

A local MCP server that uses the stdio transport is a program the client starts for you. Claude Desktop, Cursor and other clients read the `command` and `args` from their config file and start the program with Node's `child_process.spawn`.

`ENOENT` is the operating system's "no such file or directory" error. `spawn npx ENOENT` means Node looked for a program called `npx` in every folder on the client's `PATH` and did not find it. Nothing from your server ran, so there is nothing wrong with its code yet.

Most of the time `npx` is installed and works in your terminal. The client simply has a different `PATH` from the one your terminal has.

## Find your exact error

Error

Where

Cause

Fix

`spawn npx ENOENT`

macOS

Dock apps don't see Homebrew, nvm or Volta

[Absolute path plus PATH](#fix-mac)

`env: node: No such file or directory`

macOS, Linux

You gave the full path to `npx`, but `node` is still not on PATH

[Add PATH to `env`](#fix-mac)

`spawn npx ENOENT`

Windows

`npx` is a `.cmd` script, not an `.exe`

[`cmd /c npx`](#fix-windows)

`spawn EINVAL`

Windows

You used `npx.cmd` directly; newer Node refuses to start `.cmd` files without a shell

[`cmd /c npx`](#fix-windows)

`spawn npx -y @scope/server ENOENT`

Any

Arguments are inside `command`

[Move them to `args`](#fix-command)

`spawn uvx ENOENT`, `spawn docker ENOENT`

Mostly macOS

Same PATH problem, different program

[Absolute path](#uvx-docker)

## Where to find the error

Claude Desktop only shows "Server disconnected" or a red dot in the window. The full error is in its log files:

-   **macOS:** `~/Library/Logs/Claude/`. Each server has its own `mcp-server-NAME.log`, and `mcp.log` covers all of them.
-   **Windows:** `%APPDATA%\Claude\logs\`

On a Mac you can watch it live while you restart the client:

```
tail -n 50 -f ~/Library/Logs/Claude/mcp*.log
```

In Cursor, open the Output panel and choose the MCP logs from the dropdown. The config files themselves are listed in [MCP Config File Location: Claude Desktop, Cursor & Claude Code](/blog/complete-guide-mcp-config-files-claude-desktop-cursor-lovable).

## Fix on macOS: absolute path plus PATH

An app you open from the Dock, Finder or Spotlight is started by `launchd`, not by your shell. It gets the system's default PATH:

```
/usr/bin:/bin:/usr/sbin:/sbin
```

None of the usual places Node ends up are on that list: Homebrew (`/opt/homebrew/bin` on Apple Silicon, `/usr/local/bin` on Intel), nvm (`~/.nvm/versions/node/…/bin`), Volta (`~/.volta/bin`), fnm or asdf. Your terminal finds `npx` because `.zshrc` or `.zprofile` adds those folders. The Dock app never reads those files.

### Step 1: Find where npx and node are

In Terminal:

```
which npx
which node
```

You'll see something like `/opt/homebrew/bin/npx` or `/Users/you/.nvm/versions/node/v22.11.0/bin/npx`. Both are usually in the same folder.

### Step 2: Use the absolute path, and pass PATH

Put the full path in `command`, and give the server a `PATH` that includes the same folder:

```
{
  "mcpServers": {
    "filesystem": {
      "command": "/Users/you/.nvm/versions/node/v22.11.0/bin/npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/you/projects"],
      "env": {
        "PATH": "/Users/you/.nvm/versions/node/v22.11.0/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}
```

The `env` part matters. `npx` is a small script whose first line is `#!/usr/bin/env node`, so it looks up `node` on PATH as soon as it starts. With only the absolute path, the error changes to `env: node: No such file or directory`. Many people stop at that point and decide the fix didn't work.

**nvm users:** the version number is in the path, so the config breaks the next time you install a newer Node and remove the old one. Either update the path when you change versions, or point the config at a Node that keeps the same path, such as Homebrew's `/opt/homebrew/bin/npx` or Volta's `~/.volta/bin/npx`.

### Step 3: Quit and reopen the client

Closing the window is not enough. Quit Claude Desktop with Cmd+Q (or Cursor from its menu) and open it again, so it reads the config file again.

## Fix on Windows: cmd /c npx

On Windows, Node installs `npx` as `npx.cmd`, a batch script. `child_process.spawn` without a shell only starts real executables, so it can't find a program called `npx`. That gives `ENOENT`.

Writing `npx.cmd` doesn't help on current Node either. Since the April 2024 security releases (CVE-2024-27980), Node refuses to start `.cmd` and `.bat` files without a shell and throws `spawn EINVAL` instead.

Let `cmd.exe` start it for you:

```
{
  "mcpServers": {
    "filesystem": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "@modelcontextprotocol/server-filesystem", "C:\\Users\\you\\projects"]
    }
  }
}
```

Two details trip people up:

-   **Backslashes are doubled** in JSON: `C:\\Users\\you`, not `C:\Users\you`. A single backslash makes the whole file invalid, and then _every_ server disappears.
-   **If Node was installed after the client was opened**, quit the client from the system tray (not just the window) so it picks up the new PATH. If `where npx` in a new PowerShell window finds nothing, Node isn't on PATH at all; reinstall it with "Add to PATH" ticked.

## Fix everywhere: one program in "command"

This config looks reasonable, but it fails on every system:

```
"command": "npx -y @modelcontextprotocol/server-filesystem /Users/you/projects"
```

The client doesn't split `command` on spaces. It looks for one program whose name is that whole string, and the log shows the whole string in the error: `spawn npx -y @modelcontextprotocol/server-filesystem /Users/you/projects ENOENT`. Put the program alone in `command` and every word after it in `args`, one array item each:

```
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/you/projects"]
```

## Same error for uvx, node, python and docker

Any program can hit this, not only `npx`. Common ones on a Mac and where they live:

Program

Usual location

`uvx` / `uv` (official installer)

`~/.local/bin/uvx`

`uvx` (Homebrew)

`/opt/homebrew/bin/uvx`

`docker` (Docker Desktop)

`/usr/local/bin/docker`

`python3` in a virtualenv

`/path/to/project/.venv/bin/python`

Always check with `which uvx` (or `where uvx` on Windows) rather than trusting this table. For a Python server in a virtualenv, point `command` straight at the venv's `python`. That also makes sure the server gets the packages you installed.

## Check the fix before you restart the client

The usual way to test is to run the server, or the MCP Inspector, from your terminal. For this bug that test is misleading: the terminal has your full PATH, so it works there even while the client still fails.

A better check is to start the server the way the client does: from an app you opened from the Dock or Start menu, with exactly the `command`, `args` and `env` from your config.

[MCP Playground Desktop](/local-mcp-server-testing) does this and shows you what happened:

-   **Import** your Claude Desktop, Cursor, VS Code, Windsurf or Claude Code config. Each server comes in with its command, arguments and environment variables.
-   **Connect** and see the result: the tool list if it started, or the spawn error and the server's own stderr output if it didn't.
-   **On a Mac** it loads your login shell's PATH at startup, so a server that works in your terminal also works here. If it connects in MCP Playground but not in Claude Desktop, you know the server is fine and the client's PATH is the problem.
-   **On Windows** it starts `npx`, `uvx` and other `.cmd` scripts correctly, so you can test the server before you get the `cmd /c` wrapper right.

Once it connects, call a tool or two to be sure the server works, not just starts. [How to test local MCP servers](/blog/test-local-mcp-server-stdio-inspector-ai-agents) walks through that. If the server starts but then disconnects, see [MCP Server Not Working? Fix Error -32000, Timeouts, and Connection Failures](/blog/mcp-server-troubleshooting-common-errors-fix).

## Frequently Asked Questions

**Why does npx work in my terminal but not in Claude Desktop?+**

Your terminal reads .zshrc or .zprofile, which add Homebrew, nvm or Volta to PATH. Claude Desktop opened from the Dock is started by launchd with only /usr/bin:/bin:/usr/sbin:/sbin, so it can't find npx. Use the absolute path to npx and add a PATH entry in the server's env.

**I used the full path to npx and now get "env: node: No such file or directory". Why?+**

npx is a script that starts with #!/usr/bin/env node, so it still needs node on PATH. Add "env": { "PATH": "folder-containing-node:/usr/bin:/bin" } to the server's config entry.

**How do I fix spawn npx ENOENT on Windows?+**

Set "command" to "cmd" and start args with "/c", "npx", followed by the package and its arguments. npx on Windows is npx.cmd, which Node can't start without a shell. Using "npx.cmd" directly fails with spawn EINVAL on current Node versions.

**Where are Claude Desktop's MCP logs?+**

On macOS in ~/Library/Logs/Claude/ (mcp.log and one mcp-server-NAME.log per server). On Windows in %APPDATA%\\Claude\\logs\\.

**Does spawn uvx ENOENT have the same fix?+**

Yes. Find it with which uvx (usually ~/.local/bin/uvx or /opt/homebrew/bin/uvx), put that absolute path in "command", and quit and reopen the client.

## Conclusion

`spawn npx ENOENT` is almost never a bug in your server. On a Mac, give the client the absolute path and a PATH. On Windows, wrap the command in `cmd /c`. Everywhere, keep arguments out of `command`.

Then check the server outside the client, started the same way the client starts it. [Get MCP Playground Desktop for Mac and Windows →](/local-mcp-server-testing)

## Frequently asked questions

### Why does npx work in my terminal but not in Claude Desktop?

Your terminal reads .zshrc or .zprofile, which add Homebrew, nvm or Volta to PATH. Claude Desktop opened from the Dock is started by launchd with only /usr/bin:/bin:/usr/sbin:/sbin, so it can't find npx. Use the absolute path to npx and add a PATH entry in the server's env.

### I used the full path to npx and now get "env: node: No such file or directory". Why?

npx is a script that starts with #!/usr/bin/env node, so it still needs node on PATH. Add "env": { "PATH": "folder-containing-node:/usr/bin:/bin" } to the server's config entry.

### How do I fix spawn npx ENOENT on Windows?

Set "command" to "cmd" and start args with "/c", "npx", followed by the package and its arguments. npx on Windows is npx.cmd, which Node can't start without a shell. Using "npx.cmd" directly fails with spawn EINVAL on current Node versions.

### Where are Claude Desktop's MCP logs?

On macOS in ~/Library/Logs/Claude/ (mcp.log and one mcp-server-NAME.log per server). On Windows in %APPDATA%\Claude\logs\.

### Does spawn uvx ENOENT have the same fix?

Yes. Find it with which uvx (usually ~/.local/bin/uvx or /opt/homebrew/bin/uvx), put that absolute path in "command", and quit and reopen the client.


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_Canonical page: https://mcpplaygroundonline.com/blog/fix-spawn-npx-enoent-mcp — MCP Playground (mcpplaygroundonline.com), the free browser-based tool for testing MCP servers and building AI agents._