[Bug]: Cannot connect to Apify MCP server from Claude.ai on Windows 11

[poojastejwani-sketch]

Server type

Local (stdio via npx @apify/actors-mcp-server)

MCP Client

Claude Desktop

Operating System

Windows

What happened?

The Apify MCP connector in Claude.ai Desktop keeps showing
"Could not attach to MCP server Apify" and "Unable to connect
to extension server" despite all requirements being met.

Steps taken:

• Node.js v24.16.0 installed and working
• Fresh API tokens generated multiple times
• Connector uninstalled and reinstalled multiple times
• mcp.apify.com loads correctly in browser
• Connector shows "All requirements met"
• Enabled tools set correctly as: actors,docs,apify/rag-web-browser

OS: Windows 11
Claude Desktop version: latest
Apify connector version: 0.9.17

Error: "Could not attach to MCP server Apify"

Steps to reproduce

1. Open Claude Desktop on Windows 11
2. Go to Settings → Extensions → apify-mcp-server
3. Enter valid Apify API token and save
4. Enable the connector
5. Error immediately appears: "Could not attach to MCP server Apify"
6. Bottom of page shows: "Unable to connect to extension server"

Node.js version

v24.16.0

Apify MCP Server version

No response

MCP server configuration

{
  "mcpServers": {
    "apify": {
      "command": "npx",
      "args": ["-y", "@apify/actors-mcp-server"],
      "env": {
        "APIFY_TOKEN": "<REMOVED>"
      }
    }
  }
}

Error logs

Could not attach to MCP server Apify
Unable to connect to extension server. 
Please try disabling and re-enabling the extension.

[guitarmonk26]

I am having same bug and took same steps, I dont know how to enter server configuration to see code. Just posted this on discord as well. Thanks

[juliazmacha]

I’ve created custom connector using https://mcp.apify.com/

[jirispilka]

Thanks for the report. "Unable to connect to extension server" on Windows with the local stdio (npx) setup is almost always a corrupted npx cache, Node not on the GUI app's PATH, or Claude Desktop silently downgrading the connector.

The reliable fix is to skip local stdio and use our hosted server as a custom connector (as @juliazmacha did above):

1. Claude Desktop → Settings → Connectors → Add custom connector
2. URL: https://mcp.apify.com
3. Complete the OAuth flow — no API token needed in config

If you want to keep the local setup, clear the npx cache first: rmdir /s /q %LOCALAPPDATA%\npm-cache\_npx, then re-add the connector. Troubleshooting: https://docs.apify.com/platform/integrations/claude-desktop#troubleshooting