title: Local npm dependency broken since npm v5.5.1
body: <p>In our package.json we are using file-notation to reference our self developed private modules like this:</p>
  
  <pre><code>"dependencies": {
    "privateX": "file:////serverName/path/to/privateX",
    "privateY": "file:////serverName/path/to/privateY"
  }
  </code></pre>
  
  <p>This worked fine until npm v4.2.0 (with Node v7.10.1). After updating to npm v5.5.1 (with Node.js 8.9.0 LTS) we are not able to install (npm install) them anymore and get following error:</p>
  
  <pre><code>npm ERR! code ENOLOCAL
  npm ERR! Could not install from "..\..\serverName\path\to\privateX" as it does not contain a package.json file.
  </code></pre>
  
  <p>I've tried different approaches like, which didn't work either:</p>
  
  <ul>
  <li>"privateX": "file://serverName/path/to/privateX"</li>
  <li>"privateX": "file:\\\\serverName\\path\\to\\privateX"</li>
  </ul>
  
  <p><em>npm cache clean --force</em> didn't help.</p>
  
  <p>Only putting the dependencies on every server and using a relative path worked. But this is not practicable:</p>
  
  <ul>
  <li>"privateX": "file://../../path/to/privateX"</li>
  </ul>
  
  <p>When we downgrade back to npm v4.2.0 or lower it works again. What happened since that version causing to break access to another server in the same network? Or how would an approach look like to reference dependencies on another server in the same network, in npm 5.x.x and above?</p>
  
  <p>Our private modules are located on a server within our network. All servers are running on Windows. </p>