[Bug] User-level MCPB install silently never completes (org-level succeeds)

[Sam-Heyman]

Environment

• OS: Windows 11 (reproduced on multiple machines)
• Claude Desktop: current
• MCPB manifest version: 0.3
• Server type: node, entry point via mcp-remote remote proxy

What happens

Installing an .mcpb file via Claude Desktop Org Settings → Add → Custom → Desktop:

1. Org-level install prompt appears and completes successfully (Settings → Organization → Connectors → Add → Custom → Desktop)
2. User-level install shows a progress bar that never advances (Settings → Connectors → Customize → (+) → Browse Connectors → our org's connector → (+) → Install)
3. No error is shown - you can dismiss it with X
4. The extension is never installed, no matter how long you wait

What I've ruled out

• Reproduced on multiple machines with different users - not environment-specific
• Full uninstall + reinstall of Claude Desktop (including all user data) does not fix it
• MCP server connects and functions properly via manual workaround - not an issue with the .mcpb file itself

Workaround

Manually adding the server to %APPDATA%\Claude\claude_desktop_config.json:

"mcpServers": {
  "my-server": {
    "command": "npx",
    "args": ["mcp-remote@0.1.38", "https://<endpoint>/mcp"]
  }
}