title: 'vagrant up' gives 'An error occurred while downloading'
body: <p>I use Vagrant on my Linux and OS X machines without problem.
  Now on Windows 10 (the preview with Bash for Windows) it fails while downloading my box, without specifying a proper error message:</p>
  
  <pre><code>Bringing machine 'default' up with 'virtualbox' provider...
  ==&gt; default: Box 'trusty' could not be found. Attempting to find and install...
      default: Box Provider: virtualbox
      default: Box Version: &gt;= 0
  ==&gt; default: Box file was not detected as metadata. Adding it directly...
  ==&gt; default: Adding box 'trusty' (v0) for provider: virtualbox
      default: Downloading: http://cloud-images.ubuntu.com/vagrant/trusty/current/trusty-server-cloudimg-amd64-vagrant-disk1.box
      default:
  An error occurred while downloading the remote file. The error
  message, if any, is reproduced below. Please fix this error and try
  again.
  </code></pre>
  
  <p>I also tried downloading the box (so the URL is correct!) and adding it manually but this results in the same:</p>
  
  <pre><code>C:\&gt; vagrant box add ubuntu/trusty64 c:\Users\michi\boxes\trusty-server-cloudimg-amd64-vagrant-disk1.box
  ==&gt; box: Box file was not detected as metadata. Adding it directly...
  ==&gt; box: Adding box 'ubuntu/trusty64' (v0) for provider:
      box: Unpacking necessary files from: file://c:/Users/michi/boxes/trusty-server-cloudimg-amd64-vagrant-disk1.box
      box:
  An error occurred while downloading the remote file. The error
  message, if any, is reproduced below. Please fix this error and try
  again.
  </code></pre>